merge error codes

61 files changed, 2705 insertions, 3468 deletions

diff --git a/.gitignore b/.gitignore
index 5bb943a9d..5bb95cb46 100644
--- a/.gitignore
+++ b/.gitignore
@@ -59,6 +59,7 @@ src/exchange/test_taler_exchange_httpd_home/.local/share/taler/exchange/live-key
 src/exchange/test_taler_exchange_httpd_home/.local/share/taler/exchange/wirefees/
 src/exchange-tools/taler-auditor-sign
 src/exchange-tools/taler-exchange-dbinit
+src/exchange-tools/taler-exchange-tvg
 src/exchange-tools/taler-exchange-keycheck
 src/exchange-tools/taler-exchange-keyup
 src/exchange-tools/taler-exchange-wire
diff --git a/configure.ac b/configure.ac
index 44703bf1e..07fc2860b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -550,6 +550,7 @@ AC_CONFIG_FILES([Makefile
                  src/benchmark/Makefile
                  src/include/Makefile
                  src/json/Makefile
+                 src/mhd/Makefile
                  src/pq/Makefile
                  src/util/Makefile
                  src/util/taler-config
diff --git a/src/Makefile.am b/src/Makefile.am
index 38bf715fe..761b9c335 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -22,7 +22,7 @@ pkgcfg_DATA = \
 EXTRA_DIST = \
   taler.conf
 
-SUBDIRS = include util wire json curl $(PQ_DIR) $(BANK_LIB) wire-plugins exchangedb exchange exchange-tools auditordb auditor
+SUBDIRS = include util wire json curl $(PQ_DIR) mhd $(BANK_LIB) wire-plugins exchangedb exchange exchange-tools auditordb auditor
 if HAVE_LIBCURL
  SUBDIRS += lib benchmark
 else
diff --git a/src/auditor/Makefile.am b/src/auditor/Makefile.am
index e3600e20f..a1bb4d247 100644
--- a/src/auditor/Makefile.am
+++ b/src/auditor/Makefile.am
@@ -52,11 +52,10 @@ taler_auditor_httpd_SOURCES = \
   taler-auditor-httpd_db.c taler-auditor-httpd_db.h \
   taler-auditor-httpd_deposit-confirmation.c taler-auditor-httpd_deposit-confirmation.h \
   taler-auditor-httpd_exchanges.c taler-auditor-httpd_exchanges.h \
-  taler-auditor-httpd_mhd.c taler-auditor-httpd_mhd.h \
-  taler-auditor-httpd_parsing.c taler-auditor-httpd_parsing.h \
-  taler-auditor-httpd_responses.c taler-auditor-httpd_responses.h
+  taler-auditor-httpd_mhd.c taler-auditor-httpd_mhd.h
 taler_auditor_httpd_LDADD = \
   $(LIBGCRYPT_LIBS) \
+  $(top_builddir)/src/mhd/libtalermhd.la \
   $(top_builddir)/src/util/libtalerutil.la \
   $(top_builddir)/src/json/libtalerjson.la \
   $(top_builddir)/src/wire/libtalerwire.la \
diff --git a/src/auditor/taler-auditor-httpd.c b/src/auditor/taler-auditor-httpd.c
index e37b4a0e8..55a343776 100644
--- a/src/auditor/taler-auditor-httpd.c
+++ b/src/auditor/taler-auditor-httpd.c
@@ -27,11 +27,10 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include <sys/resource.h>
+#include "taler_mhd_lib.h"
 #include "taler_auditordb_lib.h"
 #include "taler-auditor-httpd_deposit-confirmation.h"
 #include "taler-auditor-httpd_exchanges.h"
-#include "taler-auditor-httpd_parsing.h"
-#include "taler-auditor-httpd_responses.h"
 #include "taler-auditor-httpd_mhd.h"
 #include "taler-auditor-httpd.h"
 
@@ -291,7 +290,7 @@ handle_mhd_completion_callback (void *cls,
 {
   if (NULL == *con_cls)
     return;
-  TAH_PARSE_post_cleanup_callback (*con_cls);
+  TALER_MHD_parse_post_cleanup_callback (*con_cls);
   *con_cls = NULL;
 }
 
@@ -332,9 +331,9 @@ handle_version (struct TAH_RequestHandler *rh,
     GNUNET_break (0);
     return MHD_NO;
   }
-  return TAH_RESPONSE_reply_json (connection,
-                                  ver,
-                                  MHD_HTTP_OK);
+  return TALER_MHD_reply_json (connection,
+                               ver,
+                               MHD_HTTP_OK);
 }
 
 
@@ -384,7 +383,7 @@ handle_mhd_request (void *cls,
       &TAH_MHD_handler_static_response, MHD_HTTP_OK },
     /* AGPL licensing page, redirect to source. As per the AGPL-license,
        every deployment is required to offer the user a download of the
-       source. We make this easy by including a redirect to the source
+       source. We make this easy by including a redirect t the source
        here. */
     { "/agpl", MHD_HTTP_METHOD_GET, "text/plain",
       NULL, 0,
@@ -392,11 +391,6 @@ handle_mhd_request (void *cls,
 
     { NULL, NULL, NULL, NULL, 0, 0 }
   };
-  static struct TAH_RequestHandler h404 = {
-    "", NULL, "text/html",
-    "<html><title>404: not found</title></html>", 0,
-    &TAH_MHD_handler_static_response, MHD_HTTP_NOT_FOUND
-  };
   struct TAH_RequestHandler *rh;
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
@@ -419,127 +413,13 @@ handle_mhd_request (void *cls,
                           upload_data,
                           upload_data_size);
   }
-  return TAH_MHD_handler_static_response (&h404,
-                                          connection,
-                                          con_cls,
-                                          upload_data,
-                                          upload_data_size);
-}
-
-
-/**
- * Parse the configuration to determine on which port
- * or UNIX domain path we should run an HTTP service.
- *
- * @param section section of the configuration to parse ("auditor" or "auditor-admin")
- * @param[out] rport set to the port number, or 0 for none
- * @param[out] unix_path set to the UNIX path, or NULL for none
- * @param[out] unix_mode set to the mode to be used for @a unix_path
- * @return #GNUNET_OK on success
- */
-static int
-parse_port_config (const char *section,
-                   uint16_t *rport,
-                   char **unix_path,
-                   mode_t *unix_mode)
-{
-  const char *choices[] = {"tcp", "unix"};
-  const char *serve_type;
-  unsigned long long port;
-
-  if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_choice (cfg,
-                                             section,
-                                             "serve",
-                                             choices,
-                                             &serve_type))
-  {
-    GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                               section,
-                               "serve",
-                               "serve type required");
-    return GNUNET_SYSERR;
-  }
-
-  if (0 == strcmp (serve_type, "tcp"))
-  {
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_number (cfg,
-                                               section,
-                                               "port",
-                                               &port))
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "port",
-                                 "port number required");
-      return GNUNET_SYSERR;
-    }
-
-    if ( (0 == port) ||
-         (port > UINT16_MAX) )
-    {
-      fprintf (stderr,
-               "Invalid configuration (value out of range): %llu is not a valid port\n",
-               port);
-      return GNUNET_SYSERR;
-    }
-    *rport = (uint16_t) port;
-    *unix_path = NULL;
-    return GNUNET_OK;
-  }
-  if (0 == strcmp (serve_type, "unix"))
-  {
-    struct sockaddr_un s_un;
-    char *modestring;
-
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_filename (cfg,
-                                                 section,
-                                                 "unixpath",
-                                                 unix_path))
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "unixpath",
-                                 "unixpath required");
-      return GNUNET_SYSERR;
-    }
-    if (strlen (*unix_path) >= sizeof (s_un.sun_path))
-    {
-      fprintf (stderr,
-               "Invalid configuration: unix path too long\n");
-      return GNUNET_SYSERR;
-    }
-
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_string (cfg,
-                                               section,
-                                               "UNIXPATH_MODE",
-                                               &modestring))
-    {
-      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "UNIXPATH_MODE");
-      return GNUNET_SYSERR;
-    }
-    errno = 0;
-    *unix_mode = (mode_t) strtoul (modestring, NULL, 8);
-    if (0 != errno)
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "UNIXPATH_MODE",
-                                 "must be octal number");
-      GNUNET_free (modestring);
-      return GNUNET_SYSERR;
-    }
-    GNUNET_free (modestring);
-    return GNUNET_OK;
-  }
-  /* not reached */
-  GNUNET_assert (0);
-  return GNUNET_SYSERR;
+#define NOT_FOUND "<html><title>404: not found</title></html>"
+  return TALER_MHD_reply_static (connection,
+                                 MHD_HTTP_NOT_FOUND,
+                                 "text/html",
+                                 NOT_FOUND,
+                                 strlen (NOT_FOUND));
+#undef NOT_FOUND
 }
 
 
@@ -562,10 +442,11 @@ auditor_serve_process_config ()
     return GNUNET_SYSERR;
   }
   if (GNUNET_OK !=
-      parse_port_config ("auditor",
-                         &serve_port,
-                         &serve_unixpath,
-                         &unixpath_mode))
+      TALER_MHD_parse_config (cfg,
+                              "auditor",
+                              &serve_port,
+                              &serve_unixpath,
+                              &unixpath_mode))
   {
     return GNUNET_SYSERR;
   }
@@ -641,141 +522,6 @@ auditor_serve_process_config ()
 
 
 /**
- * Function called for logging by MHD.
- *
- * @param cls closure, NULL
- * @param fm format string (`printf()`-style)
- * @param ap arguments to @a fm
- */
-static void
-handle_mhd_logs (void *cls,
-                 const char *fm,
-                 va_list ap)
-{
-  static int cache;
-  char buf[2048];
-
-  if (-1 == cache)
-    return;
-  if (0 == cache)
-  {
-    if (0 ==
-        GNUNET_get_log_call_status (GNUNET_ERROR_TYPE_INFO,
-                                    "auditor-httpd",
-                                    __FILE__,
-                                    __FUNCTION__,
-                                    __LINE__))
-    {
-      cache = -1;
-      return;
-    }
-  }
-  cache = 1;
-  vsnprintf (buf,
-             sizeof (buf),
-             fm,
-             ap);
-  GNUNET_log_from_nocheck (GNUNET_ERROR_TYPE_INFO,
-                           "auditor-httpd",
-                           "%s",
-                           buf);
-}
-
-
-/**
- * Open UNIX domain socket for listining at @a unix_path with
- * permissions @a unix_mode.
- *
- * @param unix_path where to listen
- * @param unix_mode access permissions to set
- * @return -1 on error, otherwise the listen socket
- */
-static int
-open_unix_path (const char *unix_path,
-                mode_t unix_mode)
-{
-  struct GNUNET_NETWORK_Handle *nh;
-  struct sockaddr_un *un;
-  int fd;
-
-  if (sizeof (un->sun_path) <= strlen (unix_path))
-  {
-    fprintf (stderr,
-             "unixpath `%s' too long\n",
-             unix_path);
-    return -1;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Creating listen socket '%s' with mode %o\n",
-              unix_path,
-              unix_mode);
-
-  if (GNUNET_OK !=
-      GNUNET_DISK_directory_create_for_file (unix_path))
-  {
-    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
-                              "mkdir",
-                              unix_path);
-  }
-
-  un = GNUNET_new (struct sockaddr_un);
-  un->sun_family = AF_UNIX;
-  strncpy (un->sun_path,
-           unix_path,
-           sizeof (un->sun_path) - 1);
-  GNUNET_NETWORK_unix_precheck (un);
-
-  if (NULL == (nh = GNUNET_NETWORK_socket_create (AF_UNIX,
-                                                  SOCK_STREAM,
-                                                  0)))
-  {
-    fprintf (stderr,
-             "create failed for AF_UNIX\n");
-    GNUNET_free (un);
-    return -1;
-  }
-  if (GNUNET_OK !=
-      GNUNET_NETWORK_socket_bind (nh,
-                                  (void *) un,
-                                  sizeof (struct sockaddr_un)))
-  {
-    fprintf (stderr,
-             "bind failed for AF_UNIX\n");
-    GNUNET_free (un);
-    GNUNET_NETWORK_socket_close (nh);
-    return -1;
-  }
-  GNUNET_free (un);
-  if (GNUNET_OK !=
-      GNUNET_NETWORK_socket_listen (nh,
-                                    UNIX_BACKLOG))
-  {
-    fprintf (stderr,
-             "listen failed for AF_UNIX\n");
-    GNUNET_NETWORK_socket_close (nh);
-    return -1;
-  }
-
-  if (0 != chmod (unix_path,
-                  unix_mode))
-  {
-    fprintf (stderr,
-             "chmod failed: %s\n",
-             strerror (errno));
-    GNUNET_NETWORK_socket_close (nh);
-    return -1;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "set socket '%s' to mode %o\n",
-              unix_path,
-              unix_mode);
-  fd = GNUNET_NETWORK_get_fd (nh);
-  GNUNET_NETWORK_socket_free_memory_only_ (nh);
-  return fd;
-}
-
-
-/**
  * The main function of the taler-auditor-httpd server ("the auditor").
  *
  * @param argc number of arguments from the command line
@@ -811,12 +557,17 @@ main (int argc,
   const char *listen_pid;
   const char *listen_fds;
   int fh = -1;
+  enum TALER_MHD_GlobalOptions go;
 
   if (0 >=
       GNUNET_GETOPT_run ("taler-auditor-httpd",
                          options,
                          argc, argv))
     return 1;
+  go = TALER_MHD_GO_NONE;
+  if (TAH_auditor_connection_close)
+    go |= TALER_MHD_GO_FORCE_CONNECTION_CLOSE;
+  TALER_MHD_setup (go);
   GNUNET_assert (GNUNET_OK ==
                  GNUNET_log_setup ("taler-auditor-httpd",
                                    (NULL == loglev) ? "INFO" : loglev,
@@ -877,8 +628,8 @@ main (int argc,
   if ( (-1 == fh) &&
        (NULL != serve_unixpath) )
   {
-    fh = open_unix_path (serve_unixpath,
-                         unixpath_mode);
+    fh = TALER_MHD_open_unix_path (serve_unixpath,
+                                   unixpath_mode);
     if (-1 == fh)
       return 1;
   }
@@ -894,7 +645,8 @@ main (int argc,
                         MHD_OPTION_THREAD_POOL_SIZE, (unsigned int) 32,
                         MHD_OPTION_LISTEN_BACKLOG_SIZE, (unsigned int) 1024,
                         MHD_OPTION_LISTEN_SOCKET, fh,
-                        MHD_OPTION_EXTERNAL_LOGGER, &handle_mhd_logs, NULL,
+                        MHD_OPTION_EXTERNAL_LOGGER, &TALER_MHD_handle_logs,
+                        NULL,
                         MHD_OPTION_NOTIFY_COMPLETED,
                         &handle_mhd_completion_callback, NULL,
                         MHD_OPTION_CONNECTION_TIMEOUT, connection_timeout,
diff --git a/src/auditor/taler-auditor-httpd_db.c b/src/auditor/taler-auditor-httpd_db.c
index e0ab8f2e1..3433e9a9f 100644
--- a/src/auditor/taler-auditor-httpd_db.c
+++ b/src/auditor/taler-auditor-httpd_db.c
@@ -23,8 +23,9 @@
 #include <jansson.h>
 #include <gnunet/gnunet_json_lib.h>
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-auditor-httpd_db.h"
-#include "taler-auditor-httpd_responses.h"
+#include "taler-auditor-httpd.h"
 
 
 /**
@@ -63,8 +64,10 @@ TAH_DB_run_transaction (struct MHD_Connection *connection,
   {
     GNUNET_break (0);
     if (NULL != mhd_ret)
-      *mhd_ret = TAH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_DB_SETUP_FAILED);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_DB_SETUP_FAILED,
+                                             "failed to establish session with database");
     return GNUNET_SYSERR;
   }
   //  TAH_plugin->preflight (TAH_plugin->cls, session); // FIXME: needed?
@@ -79,8 +82,10 @@ TAH_DB_run_transaction (struct MHD_Connection *connection,
     {
       GNUNET_break (0);
       if (NULL != mhd_ret)
-        *mhd_ret = TAH_RESPONSE_reply_internal_db_error (connection,
-                                                         TALER_EC_DB_START_FAILED);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_DB_START_FAILED,
+                                               "failed to begin transaction");
       return GNUNET_SYSERR;
     }
     qs = cb (cb_cls,
@@ -98,8 +103,10 @@ TAH_DB_run_transaction (struct MHD_Connection *connection,
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
       if (NULL != mhd_ret)
-        *mhd_ret = TAH_RESPONSE_reply_commit_error (connection,
-                                                    TALER_EC_DB_COMMIT_FAILED_HARD);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_DB_COMMIT_FAILED_HARD,
+                                               "failed to commit transaction");
       return GNUNET_SYSERR;
     }
     /* make sure callback did not violate invariants! */
@@ -112,8 +119,10 @@ TAH_DB_run_transaction (struct MHD_Connection *connection,
                    name,
                    MAX_TRANSACTION_COMMIT_RETRIES);
   if (NULL != mhd_ret)
-    *mhd_ret = TAH_RESPONSE_reply_commit_error (connection,
-                                                TALER_EC_DB_COMMIT_FAILED_ON_RETRY);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_DB_COMMIT_FAILED_ON_RETRY,
+                                           "transaction repeatedly failed to serialize");
   return GNUNET_SYSERR;
 }
 
diff --git a/src/auditor/taler-auditor-httpd_deposit-confirmation.c b/src/auditor/taler-auditor-httpd_deposit-confirmation.c
index 2b73a910a..0a121fdae 100644
--- a/src/auditor/taler-auditor-httpd_deposit-confirmation.c
+++ b/src/auditor/taler-auditor-httpd_deposit-confirmation.c
@@ -27,11 +27,10 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-auditor-httpd.h"
 #include "taler-auditor-httpd_db.h"
 #include "taler-auditor-httpd_deposit-confirmation.h"
-#include "taler-auditor-httpd_parsing.h"
-#include "taler-auditor-httpd_responses.h"
 
 
 /**
@@ -43,10 +42,10 @@
 static int
 reply_deposit_confirmation_success (struct MHD_Connection *connection)
 {
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:s}",
-                                       "status", "DEPOSIT_CONFIRMATION_OK");
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:s}",
+                                    "status", "DEPOSIT_CONFIRMATION_OK");
 }
 
 
@@ -74,8 +73,10 @@ store_exchange_signing_key_transaction (void *cls,
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
   {
     TALER_LOG_WARNING ("Failed to store exchange signing key in database\n");
-    *mhd_ret = TAH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_AUDITOR_EXCHANGE_STORE_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_AUDITOR_EXCHANGE_STORE_DB_ERROR,
+                                           "failed to persist exchange signing key");
   }
   return qs;
 }
@@ -111,8 +112,10 @@ deposit_confirmation_transaction (void *cls,
   {
     TALER_LOG_WARNING (
       "Failed to store /deposit-confirmation information in database\n");
-    *mhd_ret = TAH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_DEPOSIT_CONFIRMATION_STORE_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_DEPOSIT_CONFIRMATION_STORE_DB_ERROR,
+                                           "failed to persist deposit-confirmation data");
   }
   return qs;
 }
@@ -155,9 +158,10 @@ verify_and_execute_deposit_confirmation (struct MHD_Connection *connection,
                                   &es->master_public_key.eddsa_pub))
   {
     TALER_LOG_WARNING ("Invalid signature on exchange signing key\n");
-    return TAH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_DEPOSIT_CONFIRMATION_SIGNATURE_INVALID,
-                                                 "master_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_DEPOSIT_CONFIRMATION_SIGNATURE_INVALID,
+                                       "master_sig");
   }
 
   /* execute transaction */
@@ -187,9 +191,10 @@ verify_and_execute_deposit_confirmation (struct MHD_Connection *connection,
                                   &dc->exchange_pub.eddsa_pub))
   {
     TALER_LOG_WARNING ("Invalid signature on /deposit-confirmation request\n");
-    return TAH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_DEPOSIT_CONFIRMATION_SIGNATURE_INVALID,
-                                                 "exchange_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_DEPOSIT_CONFIRMATION_SIGNATURE_INVALID,
+                                       "exchange_sig");
   }
 
   /* execute transaction */
@@ -248,19 +253,19 @@ TAH_DEPOSIT_CONFIRMATION_handler (struct TAH_RequestHandler *rh,
     GNUNET_JSON_spec_end ()
   };
 
-  res = TAH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) ||
        (NULL == json) )
     return MHD_YES;
-  res = TAH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   es.exchange_pub = dc.exchange_pub; /* used twice! */
   dc.master_public_key = es.master_public_key;
diff --git a/src/auditor/taler-auditor-httpd_exchanges.c b/src/auditor/taler-auditor-httpd_exchanges.c
index 881c45a23..3c6bfe68f 100644
--- a/src/auditor/taler-auditor-httpd_exchanges.c
+++ b/src/auditor/taler-auditor-httpd_exchanges.c
@@ -25,11 +25,10 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-auditor-httpd.h"
 #include "taler-auditor-httpd_db.h"
 #include "taler-auditor-httpd_exchanges.h"
-#include "taler-auditor-httpd_parsing.h"
-#include "taler-auditor-httpd_responses.h"
 
 
 /**
@@ -43,10 +42,10 @@ static int
 reply_exchanges_success (struct MHD_Connection *connection,
                          json_t *ja)
 {
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "exchanges", ja);
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "exchanges", ja);
 }
 
 
@@ -108,8 +107,10 @@ list_exchanges (void *cls,
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
   {
     TALER_LOG_WARNING ("Failed to handle /exchanges in database\n");
-    *mhd_ret = TAH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_LIST_EXCHANGES_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_LIST_EXCHANGES_DB_ERROR,
+                                           "Could not fetch exchange list from database");
   }
   return qs;
 }
@@ -148,4 +149,4 @@ TAH_EXCHANGES_handler (struct TAH_RequestHandler *rh,
 }
 
 
-/* end of taler-auditor-httpd_deposit-confirmation.c */
+/* end of taler-auditor-httpd_exchanges.c */
diff --git a/src/auditor/taler-auditor-httpd_mhd.c b/src/auditor/taler-auditor-httpd_mhd.c
index 5f13691f5..01927469e 100644
--- a/src/auditor/taler-auditor-httpd_mhd.c
+++ b/src/auditor/taler-auditor-httpd_mhd.c
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014 GNUnet e.V.
+  Copyright (C) 2014-2019 Taler Systems SA
 
   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU Affero General Public License as published by the Free Software
@@ -28,7 +28,7 @@
 #include <jansson.h>
 #include <microhttpd.h>
 #include <pthread.h>
-#include "taler-auditor-httpd_responses.h"
+#include "taler_mhd_lib.h"
 #include "taler-auditor-httpd.h"
 #include "taler-auditor-httpd_mhd.h"
 
@@ -53,6 +53,9 @@ TAH_MHD_handler_static_response (struct TAH_RequestHandler *rh,
   struct MHD_Response *response;
   int ret;
 
+  (void) connection_cls;
+  (void) upload_data;
+  (void) upload_data_size;
   if (0 == rh->data_size)
     rh->data_size = strlen ((const char *) rh->data);
   response = MHD_create_response_from_buffer (rh->data_size,
@@ -63,7 +66,7 @@ TAH_MHD_handler_static_response (struct TAH_RequestHandler *rh,
     GNUNET_break (0);
     return MHD_NO;
   }
-  TAH_RESPONSE_add_global_headers (response);
+  TALER_MHD_add_global_headers (response);
   if (NULL != rh->mime_type)
     (void) MHD_add_response_header (response,
                                     MHD_HTTP_HEADER_CONTENT_TYPE,
@@ -94,38 +97,12 @@ TAH_MHD_handler_agpl_redirect (struct TAH_RequestHandler *rh,
                                const char *upload_data,
                                size_t *upload_data_size)
 {
-  const char *agpl =
-    "This server is licensed under the Affero GPL. You will now be redirected to the source code.";
-  struct MHD_Response *response;
-  int ret;
-
-  response = MHD_create_response_from_buffer (strlen (agpl),
-                                              (void *) agpl,
-                                              MHD_RESPMEM_PERSISTENT);
-  if (NULL == response)
-  {
-    GNUNET_break (0);
-    return MHD_NO;
-  }
-  TAH_RESPONSE_add_global_headers (response);
-  if (NULL != rh->mime_type)
-    (void) MHD_add_response_header (response,
-                                    MHD_HTTP_HEADER_CONTENT_TYPE,
-                                    rh->mime_type);
-  if (MHD_NO ==
-      MHD_add_response_header (response,
-                               MHD_HTTP_HEADER_LOCATION,
-                               "http://www.git.taler.net/?p=auditor.git"))
-  {
-    GNUNET_break (0);
-    MHD_destroy_response (response);
-    return MHD_NO;
-  }
-  ret = MHD_queue_response (connection,
-                            rh->response_code,
-                            response);
-  MHD_destroy_response (response);
-  return ret;
+  (void) rh;
+  (void) connection_cls;
+  (void) upload_data;
+  (void) upload_data_size;
+  return TALER_MHD_reply_agpl (connection,
+                               "http://www.git.taler.net/?p=exchange.git");
 }
 
 
@@ -147,11 +124,11 @@ TAH_MHD_handler_send_json_pack_error (struct TAH_RequestHandler *rh,
                                       const char *upload_data,
                                       size_t *upload_data_size)
 {
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       rh->response_code,
-                                       "{s:s}",
-                                       "error",
-                                       rh->data);
+  return TALER_MHD_reply_json_pack (connection,
+                                    rh->response_code,
+                                    "{s:s}",
+                                    "error",
+                                    rh->data);
 }
 
 
diff --git a/src/auditor/taler-auditor-httpd_parsing.c b/src/auditor/taler-auditor-httpd_parsing.c
deleted file mode 100644
index fb707c88f..000000000
--- a/src/auditor/taler-auditor-httpd_parsing.c
+++ /dev/null
@@ -1,284 +0,0 @@
-/*
-  This file is part of TALER
-  Copyright (C) 2014, 2015, 2016 GNUnet e.V.
-
-  TALER is free software; you can redistribute it and/or modify it under the
-  terms of the GNU Affero General Public License as published by the Free Software
-  Foundation; either version 3, or (at your option) any later version.
-
-  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
-
-  You should have received a copy of the GNU Affero General Public License along with
-  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
-*/
-
-/**
- * @file taler-auditor-httpd_parsing.c
- * @brief functions to parse incoming requests (MHD arguments and JSON snippets)
- * @author Florian Dold
- * @author Benedikt Mueller
- * @author Christian Grothoff
- */
-
-#include "platform.h"
-#include <gnunet/gnunet_util_lib.h>
-#include <gnunet/gnunet_json_lib.h>
-#include "taler_json_lib.h"
-#include "taler-auditor-httpd_parsing.h"
-#include "taler-auditor-httpd_responses.h"
-
-
-/**
- * Maximum POST request size.
- */
-#define REQUEST_BUFFER_MAX (1024 * 1024)
-
-
-/**
- * Process a POST request containing a JSON object.  This function
- * realizes an MHD POST processor that will (incrementally) process
- * JSON data uploaded to the HTTP server.  It will store the required
- * state in the @a con_cls, which must be cleaned up using
- * #TAH_PARSE_post_cleanup_callback().
- *
- * @param connection the MHD connection
- * @param con_cls the closure (points to a `struct Buffer *`)
- * @param upload_data the POST data
- * @param upload_data_size number of bytes in @a upload_data
- * @param json the JSON object for a completed request
- * @return
- *    #GNUNET_YES if json object was parsed or at least
- *               may be parsed in the future (call again);
- *               `*json` will be NULL if we need to be called again,
- *                and non-NULL if we are done.
- *    #GNUNET_NO is request incomplete or invalid
- *               (error message was generated)
- *    #GNUNET_SYSERR on internal error
- *               (we could not even queue an error message,
- *                close HTTP session with MHD_NO)
- */
-int
-TAH_PARSE_post_json (struct MHD_Connection *connection,
-                     void **con_cls,
-                     const char *upload_data,
-                     size_t *upload_data_size,
-                     json_t **json)
-{
-  enum GNUNET_JSON_PostResult pr;
-
-  pr = GNUNET_JSON_post_parser (REQUEST_BUFFER_MAX,
-                                connection,
-                                con_cls,
-                                upload_data,
-                                upload_data_size,
-                                json);
-  switch (pr)
-  {
-  case GNUNET_JSON_PR_OUT_OF_MEMORY:
-    return (MHD_NO ==
-            TAH_RESPONSE_reply_internal_error (connection,
-                                               TALER_EC_PARSER_OUT_OF_MEMORY,
-                                               "out of memory"))
-           ? GNUNET_SYSERR : GNUNET_NO;
-  case GNUNET_JSON_PR_CONTINUE:
-    return GNUNET_YES;
-  case GNUNET_JSON_PR_REQUEST_TOO_LARGE:
-    return (MHD_NO ==
-            TAH_RESPONSE_reply_request_too_large (connection))
-           ? GNUNET_SYSERR : GNUNET_NO;
-  case GNUNET_JSON_PR_JSON_INVALID:
-    return (MHD_YES ==
-            TAH_RESPONSE_reply_invalid_json (connection))
-           ? GNUNET_NO : GNUNET_SYSERR;
-  case GNUNET_JSON_PR_SUCCESS:
-    GNUNET_break (NULL != *json);
-    return GNUNET_YES;
-  }
-  /* this should never happen */
-  GNUNET_break (0);
-  return GNUNET_SYSERR;
-}
-
-
-/**
- * Function called whenever we are done with a request
- * to clean up our state.
- *
- * @param con_cls value as it was left by
- *        #TAH_PARSE_post_json(), to be cleaned up
- */
-void
-TAH_PARSE_post_cleanup_callback (void *con_cls)
-{
-  GNUNET_JSON_post_parser_cleanup (con_cls);
-}
-
-
-/**
- * Extract base32crockford encoded data from request.
- *
- * Queues an error response to the connection if the parameter is
- * missing or invalid.
- *
- * @param connection the MHD connection
- * @param param_name the name of the parameter with the key
- * @param[out] out_data pointer to store the result
- * @param out_size expected size of data
- * @return
- *   #GNUNET_YES if the the argument is present
- *   #GNUNET_NO if the argument is absent or malformed
- *   #GNUNET_SYSERR on internal error (error response could not be sent)
- */
-int
-TAH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
-                                const char *param_name,
-                                void *out_data,
-                                size_t out_size)
-{
-  const char *str;
-
-  str = MHD_lookup_connection_value (connection,
-                                     MHD_GET_ARGUMENT_KIND,
-                                     param_name);
-  if (NULL == str)
-  {
-    return (MHD_NO ==
-            TAH_RESPONSE_reply_arg_missing (connection,
-                                            TALER_EC_PARAMETER_MISSING,
-                                            param_name))
-           ? GNUNET_SYSERR : GNUNET_NO;
-  }
-  if (GNUNET_OK !=
-      GNUNET_STRINGS_string_to_data (str,
-                                     strlen (str),
-                                     out_data,
-                                     out_size))
-    return (MHD_NO ==
-            TAH_RESPONSE_reply_arg_invalid (connection,
-                                            TALER_EC_PARAMETER_MALFORMED,
-                                            param_name))
-           ? GNUNET_SYSERR : GNUNET_NO;
-  return GNUNET_OK;
-}
-
-
-/**
- * Parse JSON object into components based on the given field
- * specification.  Generates error response on parse errors.
- *
- * @param connection the connection to send an error response to
- * @param root the JSON node to start the navigation at.
- * @param[in,out] spec field specification for the parser
- * @return
- *    #GNUNET_YES if navigation was successful (caller is responsible
- *                for freeing allocated variable-size data using
- *                GNUNET_JSON_parse_free() when done)
- *    #GNUNET_NO if json is malformed, error response was generated
- *    #GNUNET_SYSERR on internal error
- */
-int
-TAH_PARSE_json_data (struct MHD_Connection *connection,
-                     const json_t *root,
-                     struct GNUNET_JSON_Specification *spec)
-{
-  int ret;
-  const char *error_json_name;
-  unsigned int error_line;
-
-  ret = GNUNET_JSON_parse (root,
-                           spec,
-                           &error_json_name,
-                           &error_line);
-  if (GNUNET_SYSERR == ret)
-  {
-    if (NULL == error_json_name)
-      error_json_name = "<no field>";
-    ret = (MHD_YES ==
-           TAH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         "{s:s, s:I, s:s, s:I}",
-                                         "error", "parse error",
-                                         "code",
-                                         (json_int_t)
-                                         TALER_EC_JSON_INVALID_WITH_DETAILS,
-                                         "field", error_json_name,
-                                         "line", (json_int_t) error_line))
-          ? GNUNET_NO : GNUNET_SYSERR;
-    return ret;
-  }
-  return GNUNET_YES;
-}
-
-
-/**
- * Parse JSON array into components based on the given field
- * specification.  Generates error response on parse errors.
- *
- * @param connection the connection to send an error response to
- * @param root the JSON node to start the navigation at.
- * @param[in,out] spec field specification for the parser
- * @param ... -1-terminated list of array offsets of type 'int'
- * @return
- *    #GNUNET_YES if navigation was successful (caller is responsible
- *                for freeing allocated variable-size data using
- *                GNUNET_JSON_parse_free() when done)
- *    #GNUNET_NO if json is malformed, error response was generated
- *    #GNUNET_SYSERR on internal error
- */
-int
-TAH_PARSE_json_array (struct MHD_Connection *connection,
-                      const json_t *root,
-                      struct GNUNET_JSON_Specification *spec,
-                      ...)
-{
-  int ret;
-  const char *error_json_name;
-  unsigned int error_line;
-  va_list ap;
-  json_int_t dim;
-
-  va_start (ap, spec);
-  dim = 0;
-  while ( (-1 != (ret = va_arg (ap, int))) &&
-          (NULL != root) )
-  {
-    dim++;
-    root = json_array_get (root, ret);
-  }
-  va_end (ap);
-  if (NULL == root)
-  {
-    ret = (MHD_YES ==
-           TAH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         "{s:s, s:I}",
-                                         "error", "parse error",
-                                         "dimension", dim))
-          ? GNUNET_NO : GNUNET_SYSERR;
-    return ret;
-  }
-  ret = GNUNET_JSON_parse (root,
-                           spec,
-                           &error_json_name,
-                           &error_line);
-  if (GNUNET_SYSERR == ret)
-  {
-    if (NULL == error_json_name)
-      error_json_name = "<no field>";
-    ret = (MHD_YES ==
-           TAH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         "{s:s, s:s, s:I}",
-                                         "error", "parse error",
-                                         "field", error_json_name,
-                                         "line", (json_int_t) error_line))
-          ? GNUNET_NO : GNUNET_SYSERR;
-    return ret;
-  }
-  return GNUNET_YES;
-}
-
-
-/* end of taler-auditor-httpd_parsing.c */
diff --git a/src/auditor/taler-auditor-httpd_parsing.h b/src/auditor/taler-auditor-httpd_parsing.h
deleted file mode 100644
index 7df76ef54..000000000
--- a/src/auditor/taler-auditor-httpd_parsing.h
+++ /dev/null
@@ -1,139 +0,0 @@
-/*
-  This file is part of TALER
-  Copyright (C) 2014, 2015, 2016 GNUnet e.V.
-
-  TALER is free software; you can redistribute it and/or modify it under the
-  terms of the GNU Affero General Public License as published by the Free Software
-  Foundation; either version 3, or (at your option) any later version.
-
-  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
-
-  You should have received a copy of the GNU Affero General Public License along with
-  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
-*/
-/**
- * @file taler-auditor-httpd_parsing.h
- * @brief functions to parse incoming requests
- * @author Florian Dold
- * @author Benedikt Mueller
- * @author Christian Grothoff
- */
-#ifndef TALER_AUDITOR_HTTPD_PARSING_H
-#define TALER_AUDITOR_HTTPD_PARSING_H
-
-#include <microhttpd.h>
-#include <jansson.h>
-#include "taler_util.h"
-#include "taler_json_lib.h"
-
-
-/**
- * Process a POST request containing a JSON object.  This
- * function realizes an MHD POST processor that will
- * (incrementally) process JSON data uploaded to the HTTP
- * server.  It will store the required state in the
- * "connection_cls", which must be cleaned up using
- * #TAH_PARSE_post_cleanup_callback().
- *
- * @param connection the MHD connection
- * @param con_cls the closure (points to a `struct Buffer *`)
- * @param upload_data the POST data
- * @param upload_data_size number of bytes in @a upload_data
- * @param json the JSON object for a completed request
- * @return
- *    #GNUNET_YES if json object was parsed or at least
- *               may be parsed in the future (call again);
- *               `*json` will be NULL if we need to be called again,
- *                and non-NULL if we are done.
- *    #GNUNET_NO is request incomplete or invalid
- *               (error message was generated)
- *    #GNUNET_SYSERR on internal error
- *               (we could not even queue an error message,
- *                close HTTP session with MHD_NO)
- */
-int
-TAH_PARSE_post_json (struct MHD_Connection *connection,
-                     void **con_cls,
-                     const char *upload_data,
-                     size_t *upload_data_size,
-                     json_t **json);
-
-
-/**
- * Function called whenever we are done with a request
- * to clean up our state.
- *
- * @param con_cls value as it was left by
- *        #TAH_PARSE_post_json(), to be cleaned up
- */
-void
-TAH_PARSE_post_cleanup_callback (void *con_cls);
-
-
-/**
- * Parse JSON object into components based on the given field
- * specification.
- *
- * @param connection the connection to send an error response to
- * @param root the JSON node to start the navigation at.
- * @param spec field specification for the parser
- * @return
- *    #GNUNET_YES if navigation was successful (caller is responsible
- *                for freeing allocated variable-size data using
- *                GNUNET_JSON_parse_free() when done)
- *    #GNUNET_NO if json is malformed, error response was generated
- *    #GNUNET_SYSERR on internal error
- */
-int
-TAH_PARSE_json_data (struct MHD_Connection *connection,
-                     const json_t *root,
-                     struct GNUNET_JSON_Specification *spec);
-
-
-/**
- * Parse JSON array into components based on the given field
- * specification.  Generates error response on parse errors.
- *
- * @param connection the connection to send an error response to
- * @param root the JSON node to start the navigation at.
- * @param[in,out] spec field specification for the parser
- * @param ... -1-terminated list of array offsets of type 'int'
- * @return
- *    #GNUNET_YES if navigation was successful (caller is responsible
- *                for freeing allocated variable-size data using
- *                GNUNET_JSON_parse_free() when done)
- *    #GNUNET_NO if json is malformed, error response was generated
- *    #GNUNET_SYSERR on internal error
- */
-int
-TAH_PARSE_json_array (struct MHD_Connection *connection,
-                      const json_t *root,
-                      struct GNUNET_JSON_Specification *spec,
-                      ...);
-
-
-/**
- * Extraxt fixed-size base32crockford encoded data from request.
- *
- * Queues an error response to the connection if the parameter is missing or
- * invalid.
- *
- * @param connection the MHD connection
- * @param param_name the name of the parameter with the key
- * @param[out] out_data pointer to store the result
- * @param out_size expected size of @a out_data
- * @return
- *   #GNUNET_YES if the the argument is present
- *   #GNUNET_NO if the argument is absent or malformed
- *   #GNUNET_SYSERR on internal error (error response could not be sent)
- */
-int
-TAH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
-                                const char *param_name,
-                                void *out_data,
-                                size_t out_size);
-
-
-#endif /* TALER_AUDITOR_HTTPD_PARSING_H */
diff --git a/src/auditor/taler-auditor-httpd_responses.c b/src/auditor/taler-auditor-httpd_responses.c
deleted file mode 100644
index 4c7b429e3..000000000
--- a/src/auditor/taler-auditor-httpd_responses.c
+++ /dev/null
@@ -1,480 +0,0 @@
-/*
-  This file is part of TALER
-  Copyright (C) 2014-2017 Inria & GNUnet e.V.
-
-  TALER is free software; you can redistribute it and/or modify it under the
-  terms of the GNU Affero General Public License as published by the Free Software
-  Foundation; either version 3, or (at your option) any later version.
-
-  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
-
-  You should have received a copy of the GNU Affero General Public License along with
-  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
-*/
-/**
- * @file taler-exchange-httpd_responses.c
- * @brief API for generating genric replies of the exchange; these
- *        functions are called TAH_RESPONSE_reply_ and they generate
- *        and queue MHD response objects for a given connection.
- * @author Florian Dold
- * @author Benedikt Mueller
- * @author Christian Grothoff
- */
-#include "platform.h"
-#include <zlib.h>
-#include "taler-auditor-httpd_responses.h"
-#include "taler_util.h"
-#include "taler_json_lib.h"
-
-
-/**
- * Add headers we want to return in every response.
- * Useful for testing, like if we want to always close
- * connections.
- *
- * @param response response to modify
- */
-void
-TAH_RESPONSE_add_global_headers (struct MHD_Response *response)
-{
-  if (TAH_auditor_connection_close)
-    GNUNET_break (MHD_YES ==
-                  MHD_add_response_header (response,
-                                           MHD_HTTP_HEADER_CONNECTION,
-                                           "close"));
-}
-
-
-/**
- * Is HTTP body deflate compression supported by the client?
- *
- * @param connection connection to check
- * @return #MHD_YES if 'deflate' compression is allowed
- *
- * Note that right now we're ignoring q-values, which is technically
- * not correct, and also do not support "*" anywhere but in a line by
- * itself.  This should eventually be fixed, see also
- * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
- */
-int
-TAH_RESPONSE_can_compress (struct MHD_Connection *connection)
-{
-  const char *ae;
-  const char *de;
-
-  ae = MHD_lookup_connection_value (connection,
-                                    MHD_HEADER_KIND,
-                                    MHD_HTTP_HEADER_ACCEPT_ENCODING);
-  if (NULL == ae)
-    return MHD_NO;
-  if (0 == strcmp (ae,
-                   "*"))
-    return MHD_YES;
-  de = strstr (ae,
-               "deflate");
-  if (NULL == de)
-    return MHD_NO;
-  if ( ( (de == ae) ||
-         (de[-1] == ',') ||
-         (de[-1] == ' ') ) &&
-       ( (de[strlen ("deflate")] == '\0') ||
-         (de[strlen ("deflate")] == ',') ||
-         (de[strlen ("deflate")] == ';') ) )
-    return MHD_YES;
-  return MHD_NO;
-}
-
-
-/**
- * Try to compress a response body.  Updates @a buf and @a buf_size.
- *
- * @param[in,out] buf pointer to body to compress
- * @param[in,out] buf_size pointer to initial size of @a buf
- * @return #MHD_YES if @a buf was compressed
- */
-int
-TAH_RESPONSE_body_compress (void **buf,
-                            size_t *buf_size)
-{
-  Bytef *cbuf;
-  uLongf cbuf_size;
-  int ret;
-
-  cbuf_size = compressBound (*buf_size);
-  cbuf = malloc (cbuf_size);
-  if (NULL == cbuf)
-    return MHD_NO;
-  ret = compress (cbuf,
-                  &cbuf_size,
-                  (const Bytef *) *buf,
-                  *buf_size);
-  if ( (Z_OK != ret) ||
-       (cbuf_size >= *buf_size) )
-  {
-    /* compression failed */
-    free (cbuf);
-    return MHD_NO;
-  }
-  free (*buf);
-  *buf = (void *) cbuf;
-  *buf_size = (size_t) cbuf_size;
-  return MHD_YES;
-}
-
-
-/**
- * Send JSON object as response.
- *
- * @param connection the MHD connection
- * @param json the json object
- * @param response_code the http response code
- * @return MHD result code
- */
-int
-TAH_RESPONSE_reply_json (struct MHD_Connection *connection,
-                         const json_t *json,
-                         unsigned int response_code)
-{
-  struct MHD_Response *resp;
-  void *json_str;
-  size_t json_len;
-  int ret;
-  int comp;
-
-  json_str = json_dumps (json,
-                         JSON_INDENT (2));
-  if (NULL == json_str)
-  {
-    /**
-     * This log helps to figure out which
-     * function called this one and assert-failed.
-     */
-    TALER_LOG_ERROR ("Aborting json-packing for HTTP code: %u\n",
-                     response_code);
-
-    GNUNET_assert (0);
-    return MHD_NO;
-  }
-  json_len = strlen (json_str);
-  /* try to compress the body */
-  comp = MHD_NO;
-  if (MHD_YES ==
-      TAH_RESPONSE_can_compress (connection))
-    comp = TAH_RESPONSE_body_compress (&json_str,
-                                       &json_len);
-  resp = MHD_create_response_from_buffer (json_len,
-                                          json_str,
-                                          MHD_RESPMEM_MUST_FREE);
-  if (NULL == resp)
-  {
-    free (json_str);
-    GNUNET_break (0);
-    return MHD_NO;
-  }
-  TAH_RESPONSE_add_global_headers (resp);
-  (void) MHD_add_response_header (resp,
-                                  MHD_HTTP_HEADER_CONTENT_TYPE,
-                                  "application/json");
-  if (MHD_YES == comp)
-  {
-    /* Need to indicate to client that body is compressed */
-    if (MHD_NO ==
-        MHD_add_response_header (resp,
-                                 MHD_HTTP_HEADER_CONTENT_ENCODING,
-                                 "deflate"))
-    {
-      GNUNET_break (0);
-      MHD_destroy_response (resp);
-      return MHD_NO;
-    }
-  }
-  ret = MHD_queue_response (connection,
-                            response_code,
-                            resp);
-  MHD_destroy_response (resp);
-  return ret;
-}
-
-
-/**
- * Function to call to handle the request by building a JSON
- * reply from a format string and varargs.
- *
- * @param connection the MHD connection to handle
- * @param response_code HTTP response code to use
- * @param fmt format string for pack
- * @param ... varargs
- * @return MHD result code
- */
-int
-TAH_RESPONSE_reply_json_pack (struct MHD_Connection *connection,
-                              unsigned int response_code,
-                              const char *fmt,
-                              ...)
-{
-  json_t *json;
-  va_list argp;
-  int ret;
-  json_error_t jerror;
-
-  va_start (argp, fmt);
-  json = json_vpack_ex (&jerror, 0, fmt, argp);
-  va_end (argp);
-  if (NULL == json)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Failed to pack JSON with format `%s': %s\n",
-                fmt,
-                jerror.text);
-    GNUNET_break (0);
-    return MHD_NO;
-  }
-  ret = TAH_RESPONSE_reply_json (connection,
-                                 json,
-                                 response_code);
-  json_decref (json);
-  return ret;
-}
-
-
-/**
- * Send a response indicating an invalid argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_arg_invalid (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "invalid parameter",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating an argument refering to a
- * resource unknown to the auditor (i.e. unknown reserve or
- * denomination key).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_arg_unknown (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_NOT_FOUND,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "unknown entity referenced",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating an invalid signature.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_signature_invalid (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec,
-                                      const char *param_name)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_UNAUTHORIZED,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "invalid signature",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating a missing argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is missing
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_arg_missing (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "missing parameter",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating permission denied.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about why access was denied
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_permission_denied (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec,
-                                      const char *hint)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_FORBIDDEN,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "permission denied",
-                                       "code", (json_int_t) ec,
-                                       "hint", hint);
-}
-
-
-/**
- * Send a response indicating an internal error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the internal error's nature
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_internal_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "internal error",
-                                       "code", (json_int_t) ec,
-                                       "hint", hint);
-}
-
-
-/**
- * Send a response indicating an external error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the error's nature
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_external_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "client error",
-                                       "code", (json_int_t) ec,
-                                       "hint", hint);
-}
-
-
-/**
- * Send a response indicating an error committing a
- * transaction (concurrent interference).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_commit_error (struct MHD_Connection *connection,
-                                 enum TALER_ErrorCode ec)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
-                                       "{s:s, s:I}",
-                                       "error", "commit failure",
-                                       "code", (json_int_t) ec);
-}
-
-
-/**
- * Send a response indicating a failure to talk to the Auditor's
- * database.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_internal_db_error (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec)
-{
-  return TAH_RESPONSE_reply_internal_error (connection,
-                                            ec,
-                                            "Failure in database interaction");
-}
-
-
-/**
- * Send a response indicating that the request was too big.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_request_too_large (struct MHD_Connection *connection)
-{
-  struct MHD_Response *resp;
-  int ret;
-
-  resp = MHD_create_response_from_buffer (0,
-                                          NULL,
-                                          MHD_RESPMEM_PERSISTENT);
-  if (NULL == resp)
-    return MHD_NO;
-  TAH_RESPONSE_add_global_headers (resp);
-  ret = MHD_queue_response (connection,
-                            MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
-                            resp);
-  MHD_destroy_response (resp);
-  return ret;
-}
-
-
-/**
- * Send a response indicating that the JSON was malformed.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_invalid_json (struct MHD_Connection *connection)
-{
-  return TAH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I}",
-                                       "error", "invalid json",
-                                       "code",
-                                       (json_int_t) TALER_EC_JSON_INVALID);
-}
-
-
-/* end of taler-auditor-httpd_responses.c */
diff --git a/src/auditor/taler-auditor-httpd_responses.h b/src/auditor/taler-auditor-httpd_responses.h
deleted file mode 100644
index 1cb5faa82..000000000
--- a/src/auditor/taler-auditor-httpd_responses.h
+++ /dev/null
@@ -1,245 +0,0 @@
-/*
-  This file is part of TALER
-  Copyright (C) 2014 GNUnet e.V.
-
-  TALER is free software; you can redistribute it and/or modify it under the
-  terms of the GNU Affero General Public License as published by the Free Software
-  Foundation; either version 3, or (at your option) any later version.
-
-  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
-
-  You should have received a copy of the GNU Affero General Public License along with
-  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
-*/
-
-/**
- * @file taler-auditor-httpd_responses.h
- * @brief API for generating generic replies of the auditor; these
- *        functions are called TAH_RESPONSE_reply_ and they generate
- *        and queue MHD response objects for a given connection.
- * @author Florian Dold
- * @author Benedikt Mueller
- * @author Christian Grothoff
- */
-#ifndef TALER_AUDITOR_HTTPD_RESPONSES_H
-#define TALER_AUDITOR_HTTPD_RESPONSES_H
-#include <gnunet/gnunet_util_lib.h>
-#include <jansson.h>
-#include <microhttpd.h>
-#include <pthread.h>
-#include "taler_error_codes.h"
-#include "taler-auditor-httpd.h"
-
-
-/**
- * Add headers we want to return in every response.
- * Useful for testing, like if we want to always close
- * connections.
- *
- * @param response response to modify
- */
-void
-TAH_RESPONSE_add_global_headers (struct MHD_Response *response);
-
-
-/**
- * Try to compress a response body.  Updates @a buf and @a buf_size.
- *
- * @param[in,out] buf pointer to body to compress
- * @param[in,out] buf_size pointer to initial size of @a buf
- * @return #MHD_YES if @a buf was compressed
- */
-int
-TAH_RESPONSE_body_compress (void **buf,
-                            size_t *buf_size);
-
-
-/**
- * Is HTTP body deflate compression supported by the client?
- *
- * @param connection connection to check
- * @return #MHD_YES if 'deflate' compression is allowed
- */
-int
-TAH_RESPONSE_can_compress (struct MHD_Connection *connection);
-
-
-/**
- * Send JSON object as response.
- *
- * @param connection the MHD connection
- * @param json the json object
- * @param response_code the http response code
- * @return MHD result code
- */
-int
-TAH_RESPONSE_reply_json (struct MHD_Connection *connection,
-                         const json_t *json,
-                         unsigned int response_code);
-
-
-/**
- * Function to call to handle the request by building a JSON
- * reply from a format string and varargs.
- *
- * @param connection the MHD connection to handle
- * @param response_code HTTP response code to use
- * @param fmt format string for pack
- * @param ... varargs
- * @return MHD result code
- */
-int
-TAH_RESPONSE_reply_json_pack (struct MHD_Connection *connection,
-                              unsigned int response_code,
-                              const char *fmt,
-                              ...);
-
-
-/**
- * Send a response indicating an invalid signature.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_signature_invalid (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec,
-                                      const char *param_name);
-
-
-/**
- * Send a response indicating an invalid argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return MHD result code
- */
-int
-TAH_RESPONSE_reply_arg_invalid (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name);
-
-
-/**
- * Send a response indicating an argument refering to a
- * resource unknown to the auditor (i.e. unknown reserve or
- * denomination key).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_arg_unknown (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name);
-
-
-/**
- * Send a response indicating a missing argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is missing
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_arg_missing (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name);
-
-
-/**
- * Send a response indicating permission denied.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about why access was denied
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_permission_denied (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec,
-                                      const char *hint);
-
-
-/**
- * Send a response indicating an internal error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the internal error's nature
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_internal_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint);
-
-
-/**
- * Send a response indicating an external error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the error's nature
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_external_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint);
-
-
-/**
- * Send a response indicating an error committing a
- * transaction (concurrent interference).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_commit_error (struct MHD_Connection *connection,
-                                 enum TALER_ErrorCode ec);
-
-/**
- * Send a response indicating a failure to talk to the Auditor's
- * database.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_internal_db_error (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec);
-
-
-/**
- * Send a response indicating that the request was too big.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_request_too_large (struct MHD_Connection *connection);
-
-
-/**
- * Send a response indicating that the JSON was malformed.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TAH_RESPONSE_reply_invalid_json (struct MHD_Connection *connectionx);
-
-
-#endif
diff --git a/src/exchange-tools/Makefile.am b/src/exchange-tools/Makefile.am
index 409c6bfdd..64b4cee87 100644
--- a/src/exchange-tools/Makefile.am
+++ b/src/exchange-tools/Makefile.am
@@ -16,6 +16,7 @@ bin_PROGRAMS = \
   taler-exchange-keycheck \
   taler-exchange-wire \
   taler-exchange-dbinit \
+  taler-exchange-tvg \
   taler-wire
 
 taler_wire_SOURCES = \
@@ -59,6 +60,13 @@ taler_exchange_keycheck_LDADD = \
   -lgnunetutil  $(XLIB)
 taler_exchange_keycheck_LDFLAGS = $(POSTGRESQL_LDFLAGS)
 
+taler_exchange_tvg_SOURCES = \
+  taler-exchange-tvg.c
+taler_exchange_tvg_LDADD = \
+  $(LIBGCRYPT_LIBS) \
+  $(top_builddir)/src/util/libtalerutil.la \
+  -lgnunetutil  $(XLIB)
+
 taler_exchange_dbinit_SOURCES = \
   taler-exchange-dbinit.c
 taler_exchange_dbinit_LDADD = \
diff --git a/src/exchange-tools/taler-exchange-tvg.c b/src/exchange-tools/taler-exchange-tvg.c
new file mode 100644
index 000000000..55e658fc4
--- /dev/null
+++ b/src/exchange-tools/taler-exchange-tvg.c
@@ -0,0 +1,259 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2019 GNUnet e.V.
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+/**
+ * @file exchange-tools/taler-exchange-tvg.c
+ * @brief Generate test vectors for cryptographic operations.
+ * @author Florian Dold
+ */
+#include "platform.h"
+#include "taler_util.h"
+#include "taler_signatures.h"
+#include <gnunet/gnunet_util_lib.h>
+
+
+/**
+ * Print data base32-crockford with a preceding label.
+ *
+ * @param label label to print
+ * @param data data to print
+ * @param size size of data
+ */
+static void
+display_data (char *label, void *data, size_t size)
+{
+  char *enc = GNUNET_STRINGS_data_to_string_alloc (data, size);
+  printf ("%s %s\n", label, enc);
+  GNUNET_free (enc);
+}
+
+
+/**
+ * Main function that will be run.
+ *
+ * @param cls closure
+ * @param args remaining command-line arguments
+ * @param cfgfile name of the configuration file used (for saving, can be NULL!)
+ * @param cfg configuration
+ */
+static void
+run (void *cls,
+     char *const *args,
+     const char *cfgfile,
+     const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  {
+    struct GNUNET_HashCode hc;
+    char *str = "Hello, GNU Taler";
+
+    GNUNET_CRYPTO_hash (str, strlen (str), &hc);
+
+    printf ("hash code:\n");
+    display_data ("  input", str, strlen (str));
+    display_data ("  output", &hc, sizeof (struct GNUNET_HashCode));
+  }
+  {
+    struct GNUNET_CRYPTO_EcdhePrivateKey *priv1;
+    struct GNUNET_CRYPTO_EcdhePublicKey pub1;
+    struct GNUNET_CRYPTO_EcdhePrivateKey *priv2;
+    struct GNUNET_HashCode skm;
+    priv1 = GNUNET_CRYPTO_ecdhe_key_create ();
+    priv2 = GNUNET_CRYPTO_ecdhe_key_create ();
+    GNUNET_CRYPTO_ecdhe_key_get_public (priv1, &pub1);
+    GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_ecc_ecdh (priv2, &pub1, &skm));
+
+    printf ("ecdhe key:\n");
+    display_data ("  priv1", priv1, sizeof (struct
+                                            GNUNET_CRYPTO_EcdhePrivateKey));
+    display_data ("  pub1", &pub1, sizeof (struct
+                                           GNUNET_CRYPTO_EcdhePublicKey));
+    display_data ("  priv2", priv2, sizeof (struct
+                                            GNUNET_CRYPTO_EcdhePrivateKey));
+    display_data ("  skm", &skm, sizeof (struct GNUNET_HashCode));
+    GNUNET_free (priv1);
+    GNUNET_free (priv2);
+  }
+
+  {
+    struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
+    struct GNUNET_CRYPTO_EddsaPublicKey pub;
+    priv = GNUNET_CRYPTO_eddsa_key_create ();
+    GNUNET_CRYPTO_eddsa_key_get_public (priv, &pub);
+
+    printf ("eddsa key:\n");
+    display_data ("  priv", priv, sizeof (struct
+                                          GNUNET_CRYPTO_EddsaPrivateKey));
+    display_data ("  pub", &pub, sizeof (struct GNUNET_CRYPTO_EddsaPublicKey));
+    GNUNET_free (priv);
+  }
+  {
+    struct GNUNET_CRYPTO_EddsaPrivateKey *priv;
+    struct GNUNET_CRYPTO_EddsaPublicKey pub;
+    struct GNUNET_CRYPTO_EddsaSignature sig;
+    struct TALER_ProposalDataPS data = { 0 };
+    priv = GNUNET_CRYPTO_eddsa_key_create ();
+    GNUNET_CRYPTO_eddsa_key_get_public (priv, &pub);
+    data.purpose.size = htonl (sizeof (struct TALER_ProposalDataPS));
+    GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_eddsa_sign (priv, &data.purpose,
+                                                          &sig));
+    GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_eddsa_verify (0,
+                                                            &data.purpose,
+                                                            &sig,
+                                                            &pub));
+
+    printf ("eddsa sig:\n");
+    display_data ("  priv", priv, sizeof (struct
+                                          GNUNET_CRYPTO_EddsaPrivateKey));
+    display_data ("  pub", &pub, sizeof (struct GNUNET_CRYPTO_EddsaPublicKey));
+    display_data ("  data", &data, sizeof (struct TALER_ProposalDataPS));
+    display_data ("  sig", &sig, sizeof (struct GNUNET_CRYPTO_EddsaSignature));
+    GNUNET_free (priv);
+  }
+
+  {
+    size_t out_len = 64;
+    char out[out_len];
+    char *ikm = "I'm the secret input key material";
+    char *salt = "I'm very salty";
+    char *ctx = "I'm a context chunk, also known as 'info' in the RFC";
+
+    GNUNET_assert (GNUNET_OK == GNUNET_CRYPTO_kdf (&out,
+                                                   out_len,
+                                                   salt,
+                                                   strlen (salt),
+                                                   ikm,
+                                                   strlen (ikm),
+                                                   ctx,
+                                                   strlen (ctx),
+                                                   NULL));
+
+    printf ("kdf:\n");
+    display_data ("  salt", salt, strlen (salt));
+    display_data ("  ikm", ikm, strlen (ikm));
+    display_data ("  ctx", ctx, strlen (ctx));
+    printf ("  out_len %u\n", (unsigned int) out_len);
+    display_data ("  out", out, out_len);
+  }
+  {
+    struct GNUNET_CRYPTO_EcdhePrivateKey *priv_ecdhe;
+    struct GNUNET_CRYPTO_EcdhePublicKey pub_ecdhe;
+    struct GNUNET_CRYPTO_EddsaPrivateKey *priv_eddsa;
+    struct GNUNET_CRYPTO_EddsaPublicKey pub_eddsa;
+    struct GNUNET_HashCode key_material;
+    priv_ecdhe = GNUNET_CRYPTO_ecdhe_key_create ();
+    GNUNET_CRYPTO_ecdhe_key_get_public (priv_ecdhe, &pub_ecdhe);
+    priv_eddsa = GNUNET_CRYPTO_eddsa_key_create ();
+    GNUNET_CRYPTO_eddsa_key_get_public (priv_eddsa, &pub_eddsa);
+    GNUNET_CRYPTO_ecdh_eddsa (priv_ecdhe, &pub_eddsa, &key_material);
+
+    printf ("eddsa_ecdh:\n");
+    display_data ("  priv_ecdhe", priv_ecdhe, sizeof (struct
+                                                      GNUNET_CRYPTO_EcdhePrivateKey));
+    display_data ("  pub_ecdhe", &pub_ecdhe, sizeof (struct
+                                                     GNUNET_CRYPTO_EcdhePublicKey));
+    display_data ("  priv_eddsa", priv_eddsa, sizeof (struct
+                                                      GNUNET_CRYPTO_EddsaPrivateKey));
+    display_data ("  pub_eddsa", &pub_eddsa, sizeof (struct
+                                                     GNUNET_CRYPTO_EddsaPublicKey));
+    display_data ("  key_material", &key_material, sizeof (struct
+                                                           GNUNET_HashCode));
+  }
+
+  {
+    struct GNUNET_CRYPTO_RsaPrivateKey *skey;
+    struct GNUNET_CRYPTO_RsaPublicKey *pkey;
+    struct GNUNET_HashCode message_hash;
+    struct GNUNET_CRYPTO_RsaBlindingKeySecret bks;
+    struct GNUNET_CRYPTO_RsaSignature *blinded_sig;
+    struct GNUNET_CRYPTO_RsaSignature *sig;
+    char *blinded_data;
+    size_t blinded_len;
+    char *public_enc_data;
+    size_t public_enc_len;
+    char *blinded_sig_enc_data;
+    size_t blinded_sig_enc_length;
+    char *sig_enc_data;
+    size_t sig_enc_length;
+    skey = GNUNET_CRYPTO_rsa_private_key_create (2048);
+    pkey = GNUNET_CRYPTO_rsa_private_key_get_public (skey);
+    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK, &message_hash,
+                                sizeof (struct GNUNET_HashCode));
+    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_WEAK, &bks, sizeof (struct
+                                                                          GNUNET_CRYPTO_RsaBlindingKeySecret));
+    GNUNET_assert (GNUNET_YES == GNUNET_CRYPTO_rsa_blind (&message_hash, &bks,
+                                                          pkey, &blinded_data,
+                                                          &blinded_len));
+    blinded_sig = GNUNET_CRYPTO_rsa_sign_blinded (skey, blinded_data,
+                                                  blinded_len);
+    sig = GNUNET_CRYPTO_rsa_unblind (blinded_sig, &bks, pkey);
+    GNUNET_assert (GNUNET_YES == GNUNET_CRYPTO_rsa_verify (&message_hash, sig,
+                                                           pkey));
+    public_enc_len = GNUNET_CRYPTO_rsa_public_key_encode (pkey,
+                                                          &public_enc_data);
+    blinded_sig_enc_length = GNUNET_CRYPTO_rsa_signature_encode (blinded_sig,
+                                                                 &
+                                                                 blinded_sig_enc_data);
+    sig_enc_length = GNUNET_CRYPTO_rsa_signature_encode (sig, &sig_enc_data);
+    printf ("blind signing:\n");
+    display_data ("  message_hash", &message_hash, sizeof (struct
+                                                           GNUNET_HashCode));
+    display_data ("  rsa_public_key", public_enc_data, public_enc_len);
+    display_data ("  blinding_key_secret", &bks, sizeof (struct
+                                                         GNUNET_CRYPTO_RsaBlindingKeySecret));
+    display_data ("  blinded_message", blinded_data, blinded_len);
+    display_data ("  blinded_sig", blinded_sig_enc_data,
+                  blinded_sig_enc_length);
+    display_data ("  sig", sig_enc_data, sig_enc_length);
+    GNUNET_CRYPTO_rsa_private_key_free (skey);
+    GNUNET_CRYPTO_rsa_public_key_free (pkey);
+    GNUNET_CRYPTO_rsa_signature_free (sig);
+    GNUNET_CRYPTO_rsa_signature_free (blinded_sig);
+  }
+}
+
+
+/**
+ * The main function of the test vector generation tool.
+ *
+ * @param argc number of arguments from the command line
+ * @param argv command line arguments
+ * @return 0 ok, 1 on error
+ */
+int
+main (int argc,
+      char *const *argv)
+{
+  const struct GNUNET_GETOPT_CommandLineOption options[] = {
+    GNUNET_GETOPT_OPTION_END
+  };
+
+  /* force linker to link against libtalerutil; if we do
+     not do this, the linker may "optimize" libtalerutil
+     away and skip #TALER_OS_init(), which we do need */
+  (void) TALER_project_data_default ();
+  GNUNET_assert (GNUNET_OK ==
+                 GNUNET_log_setup ("taler-exchange-dbinit",
+                                   "INFO",
+                                   NULL));
+  if (GNUNET_OK !=
+      GNUNET_PROGRAM_run (argc, argv,
+                          "taler-exchange-tvg",
+                          "Generate test vectors",
+                          options,
+                          &run, NULL))
+    return 1;
+  return 0;
+}
diff --git a/src/exchange/Makefile.am b/src/exchange/Makefile.am
index b5419a7a6..8e1621821 100644
--- a/src/exchange/Makefile.am
+++ b/src/exchange/Makefile.am
@@ -47,7 +47,6 @@ taler_exchange_httpd_SOURCES = \
   taler-exchange-httpd_deposit.c taler-exchange-httpd_deposit.h \
   taler-exchange-httpd_keystate.c taler-exchange-httpd_keystate.h \
   taler-exchange-httpd_mhd.c taler-exchange-httpd_mhd.h \
-  taler-exchange-httpd_parsing.c taler-exchange-httpd_parsing.h \
   taler-exchange-httpd_payback.c taler-exchange-httpd_payback.h \
   taler-exchange-httpd_refresh_link.c taler-exchange-httpd_refresh_link.h \
   taler-exchange-httpd_refresh_melt.c taler-exchange-httpd_refresh_melt.h \
@@ -63,6 +62,7 @@ taler_exchange_httpd_SOURCES = \
 taler_exchange_httpd_LDADD = \
   $(LIBGCRYPT_LIBS) \
   $(top_builddir)/src/wire/libtalerwire.la \
+  $(top_builddir)/src/mhd/libtalermhd.la \
   $(top_builddir)/src/json/libtalerjson.la \
   $(top_builddir)/src/exchangedb/libtalerexchangedb.la \
   $(top_builddir)/src/util/libtalerutil.la \
diff --git a/src/exchange/taler-exchange-aggregator.c b/src/exchange/taler-exchange-aggregator.c
index 95f56d0df..98de86da0 100644
--- a/src/exchange/taler-exchange-aggregator.c
+++ b/src/exchange/taler-exchange-aggregator.c
@@ -1960,10 +1960,10 @@ main (int argc,
                           options,
                           &run, NULL))
   {
-    GNUNET_free ((void*) argv);
+    GNUNET_free ((void *) argv);
     return 1;
   }
-  GNUNET_free ((void*) argv);
+  GNUNET_free ((void *) argv);
   return global_ret;
 }
 
diff --git a/src/exchange/taler-exchange-httpd.c b/src/exchange/taler-exchange-httpd.c
index af38a605a..30efb8bc2 100644
--- a/src/exchange/taler-exchange-httpd.c
+++ b/src/exchange/taler-exchange-httpd.c
@@ -27,7 +27,7 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include <sys/resource.h>
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_mhd.h"
 #include "taler-exchange-httpd_deposit.h"
 #include "taler-exchange-httpd_refund.h"
@@ -174,7 +174,7 @@ handle_mhd_completion_callback (void *cls,
               "Request completed\n");
   if (NULL == ecls)
     return;
-  TEH_PARSE_post_cleanup_callback (ecls->opaque_post_parsing_context);
+  TALER_MHD_parse_post_cleanup_callback (ecls->opaque_post_parsing_context);
   GNUNET_free (ecls);
   *con_cls = NULL;
   /* check that we didn't leave any transactions hanging */
@@ -487,122 +487,6 @@ handle_mhd_request (void *cls,
 
 
 /**
- * Parse the configuration to determine on which port
- * or UNIX domain path we should run an HTTP service.
- *
- * @param section section of the configuration to parse (usually "exchange")
- * @param[out] rport set to the port number, or 0 for none
- * @param[out] unix_path set to the UNIX path, or NULL for none
- * @param[out] unix_mode set to the mode to be used for @a unix_path
- * @return #GNUNET_OK on success
- */
-static int
-parse_port_config (const char *section,
-                   uint16_t *rport,
-                   char **unix_path,
-                   mode_t *unix_mode)
-{
-  const char *choices[] = {"tcp", "unix"};
-  const char *serve_type;
-  unsigned long long port;
-
-  if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_choice (cfg,
-                                             section,
-                                             "serve",
-                                             choices,
-                                             &serve_type))
-  {
-    GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                               section,
-                               "serve",
-                               "serve type required");
-    return GNUNET_SYSERR;
-  }
-
-  if (0 == strcasecmp (serve_type, "tcp"))
-  {
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_number (cfg,
-                                               section,
-                                               "port",
-                                               &port))
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "port",
-                                 "port number required");
-      return GNUNET_SYSERR;
-    }
-
-    if ( (0 == port) ||
-         (port > UINT16_MAX) )
-    {
-      fprintf (stderr,
-               "Invalid configuration (value out of range): %llu is not a valid port\n",
-               port);
-      return GNUNET_SYSERR;
-    }
-    *rport = (uint16_t) port;
-    *unix_path = NULL;
-    return GNUNET_OK;
-  }
-  if (0 == strcmp (serve_type, "unix"))
-  {
-    struct sockaddr_un s_un;
-    char *modestring;
-
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_filename (cfg,
-                                                 section,
-                                                 "unixpath",
-                                                 unix_path))
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "unixpath",
-                                 "unixpath required");
-      return GNUNET_SYSERR;
-    }
-    if (strlen (*unix_path) >= sizeof (s_un.sun_path))
-    {
-      fprintf (stderr,
-               "Invalid configuration: unix path too long\n");
-      return GNUNET_SYSERR;
-    }
-
-    if (GNUNET_OK !=
-        GNUNET_CONFIGURATION_get_value_string (cfg,
-                                               section,
-                                               "UNIXPATH_MODE",
-                                               &modestring))
-    {
-      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "UNIXPATH_MODE");
-      return GNUNET_SYSERR;
-    }
-    errno = 0;
-    *unix_mode = (mode_t) strtoul (modestring, NULL, 8);
-    if (0 != errno)
-    {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "UNIXPATH_MODE",
-                                 "must be octal number");
-      GNUNET_free (modestring);
-      return GNUNET_SYSERR;
-    }
-    GNUNET_free (modestring);
-    return GNUNET_OK;
-  }
-  /* not reached */
-  GNUNET_assert (0);
-  return GNUNET_SYSERR;
-}
-
-
-/**
  * Load configuration parameters for the exchange
  * server into the corresponding global variables.
  *
@@ -717,10 +601,11 @@ exchange_serve_process_config ()
   }
 
   if (GNUNET_OK !=
-      parse_port_config ("exchange",
-                         &serve_port,
-                         &serve_unixpath,
-                         &unixpath_mode))
+      TALER_MHD_parse_config (cfg,
+                              "exchange",
+                              &serve_port,
+                              &serve_unixpath,
+                              &unixpath_mode))
   {
     TEH_VALIDATION_done ();
     return GNUNET_SYSERR;
@@ -843,141 +728,6 @@ connection_done (void *cls,
 /* end of HAVE_DEVELOPER */
 #endif
 
-/**
- * Function called for logging by MHD.
- *
- * @param cls closure, NULL
- * @param fm format string (`printf()`-style)
- * @param ap arguments to @a fm
- */
-static void
-handle_mhd_logs (void *cls,
-                 const char *fm,
-                 va_list ap)
-{
-  static int cache;
-  char buf[2048];
-
-  (void) cls;
-  if (-1 == cache)
-    return;
-  if (0 == cache)
-  {
-    if (0 ==
-        GNUNET_get_log_call_status (GNUNET_ERROR_TYPE_INFO,
-                                    "libmicrohttpd",
-                                    __FILE__,
-                                    __FUNCTION__,
-                                    __LINE__))
-    {
-      cache = -1;
-      return;
-    }
-  }
-  cache = 1;
-  vsnprintf (buf,
-             sizeof (buf),
-             fm,
-             ap);
-  GNUNET_log_from_nocheck (GNUNET_ERROR_TYPE_INFO,
-                           "libmicrohttpd",
-                           "%s",
-                           buf);
-}
-
-
-/**
- * Open UNIX domain socket for listining at @a unix_path with
- * permissions @a unix_mode.
- *
- * @param unix_path where to listen
- * @param unix_mode access permissions to set
- * @return -1 on error, otherwise the listen socket
- */
-static int
-open_unix_path (const char *unix_path,
-                mode_t unix_mode)
-{
-  struct GNUNET_NETWORK_Handle *nh;
-  struct sockaddr_un *un;
-  int fd;
-
-  if (sizeof (un->sun_path) <= strlen (unix_path))
-  {
-    fprintf (stderr,
-             "unixpath `%s' too long\n",
-             unix_path);
-    return -1;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Creating listen socket '%s' with mode %o\n",
-              unix_path,
-              unix_mode);
-
-  if (GNUNET_OK !=
-      GNUNET_DISK_directory_create_for_file (unix_path))
-  {
-    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
-                              "mkdir",
-                              unix_path);
-  }
-
-  un = GNUNET_new (struct sockaddr_un);
-  un->sun_family = AF_UNIX;
-  strncpy (un->sun_path,
-           unix_path,
-           sizeof (un->sun_path) - 1);
-  GNUNET_NETWORK_unix_precheck (un);
-
-  if (NULL == (nh = GNUNET_NETWORK_socket_create (AF_UNIX,
-                                                  SOCK_STREAM,
-                                                  0)))
-  {
-    fprintf (stderr,
-             "create failed for AF_UNIX\n");
-    GNUNET_free (un);
-    return -1;
-  }
-  if (GNUNET_OK !=
-      GNUNET_NETWORK_socket_bind (nh,
-                                  (void *) un,
-                                  sizeof (struct sockaddr_un)))
-  {
-    fprintf (stderr,
-             "bind failed for AF_UNIX\n");
-    GNUNET_free (un);
-    GNUNET_NETWORK_socket_close (nh);
-    return -1;
-  }
-  GNUNET_free (un);
-  if (GNUNET_OK !=
-      GNUNET_NETWORK_socket_listen (nh,
-                                    UNIX_BACKLOG))
-  {
-    fprintf (stderr,
-             "listen failed for AF_UNIX\n");
-    GNUNET_NETWORK_socket_close (nh);
-    return -1;
-  }
-
-  if (0 != chmod (unix_path,
-                  unix_mode))
-  {
-    fprintf (stderr,
-             "chmod failed: %s\n",
-             strerror (errno));
-    GNUNET_NETWORK_socket_close (nh);
-    return -1;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "set socket '%s' to mode %o\n",
-              unix_path,
-              unix_mode);
-  fd = GNUNET_NETWORK_get_fd (nh);
-  GNUNET_NETWORK_socket_free_memory_only_ (nh);
-  return fd;
-}
-
 
 /**
  * Called when the main thread exits, writes out performance
@@ -986,7 +736,6 @@ open_unix_path (const char *unix_path,
 static void
 write_stats ()
 {
-
   struct GNUNET_DISK_FileHandle *fh;
   pid_t pid = getpid ();
   char *benchmark_dir;
@@ -1074,12 +823,17 @@ main (int argc,
   const char *listen_pid;
   const char *listen_fds;
   int fh = -1;
+  enum TALER_MHD_GlobalOptions go;
 
   if (0 >=
       GNUNET_GETOPT_run ("taler-exchange-httpd",
                          options,
                          argc, argv))
     return 1;
+  go = TALER_MHD_GO_NONE;
+  if (TEH_exchange_connection_close)
+    go |= TALER_MHD_GO_FORCE_CONNECTION_CLOSE;
+  TALER_MHD_setup (go);
   GNUNET_assert (GNUNET_OK ==
                  GNUNET_log_setup ("taler-exchange-httpd",
                                    (NULL == loglev) ? "INFO" : loglev,
@@ -1138,8 +892,8 @@ main (int argc,
   if ( (-1 == fh) &&
        (NULL != serve_unixpath) )
   {
-    fh = open_unix_path (serve_unixpath,
-                         unixpath_mode);
+    fh = TALER_MHD_open_unix_path (serve_unixpath,
+                                   unixpath_mode);
     if (-1 == fh)
       return 1;
   }
@@ -1155,7 +909,8 @@ main (int argc,
                         MHD_OPTION_THREAD_POOL_SIZE, (unsigned int) 32,
                         MHD_OPTION_LISTEN_BACKLOG_SIZE, (unsigned int) 1024,
                         MHD_OPTION_LISTEN_SOCKET, fh,
-                        MHD_OPTION_EXTERNAL_LOGGER, &handle_mhd_logs, NULL,
+                        MHD_OPTION_EXTERNAL_LOGGER, &TALER_MHD_handle_logs,
+                        NULL,
                         MHD_OPTION_NOTIFY_COMPLETED,
                         &handle_mhd_completion_callback, NULL,
                         MHD_OPTION_CONNECTION_TIMEOUT, connection_timeout,
diff --git a/src/exchange/taler-exchange-httpd_db.c b/src/exchange/taler-exchange-httpd_db.c
index 37bd23792..19781f97f 100644
--- a/src/exchange/taler-exchange-httpd_db.c
+++ b/src/exchange/taler-exchange-httpd_db.c
@@ -23,6 +23,7 @@
 #include <jansson.h>
 #include <gnunet/gnunet_json_lib.h>
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_keystate.h"
 
@@ -62,8 +63,10 @@ TEH_DB_know_coin_transaction (void *cls,
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
   {
     *mhd_ret
-      = TEH_RESPONSE_reply_internal_db_error (connection,
-                                              TALER_EC_DB_COIN_HISTORY_STORE_ERROR);
+      = TALER_MHD_reply_with_error (connection,
+                                    MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                    TALER_EC_DB_COIN_HISTORY_STORE_ERROR,
+                                    "could not persist coin data");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   return qs;
@@ -99,8 +102,10 @@ TEH_DB_run_transaction (struct MHD_Connection *connection,
   {
     GNUNET_break (0);
     if (NULL != mhd_ret)
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_DB_SETUP_FAILED);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_DB_SETUP_FAILED,
+                                             "could not establish database session");
     return GNUNET_SYSERR;
   }
   TEH_plugin->preflight (TEH_plugin->cls,
@@ -117,8 +122,10 @@ TEH_DB_run_transaction (struct MHD_Connection *connection,
     {
       GNUNET_break (0);
       if (NULL != mhd_ret)
-        *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                         TALER_EC_DB_START_FAILED);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_DB_START_FAILED,
+                                               "could not begin transaction");
       return GNUNET_SYSERR;
     }
     qs = cb (cb_cls,
@@ -136,8 +143,10 @@ TEH_DB_run_transaction (struct MHD_Connection *connection,
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
       if (NULL != mhd_ret)
-        *mhd_ret = TEH_RESPONSE_reply_commit_error (connection,
-                                                    TALER_EC_DB_COMMIT_FAILED_HARD);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_DB_COMMIT_FAILED_HARD,
+                                               "could not commit database transaction");
       return GNUNET_SYSERR;
     }
     /* make sure callback did not violate invariants! */
@@ -150,8 +159,10 @@ TEH_DB_run_transaction (struct MHD_Connection *connection,
                    name,
                    MAX_TRANSACTION_COMMIT_RETRIES);
   if (NULL != mhd_ret)
-    *mhd_ret = TEH_RESPONSE_reply_commit_error (connection,
-                                                TALER_EC_DB_COMMIT_FAILED_ON_RETRY);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_DB_COMMIT_FAILED_ON_RETRY,
+                                           "repatedly failed to serialize database transaction");
   return GNUNET_SYSERR;
 }
 
diff --git a/src/exchange/taler-exchange-httpd_deposit.c b/src/exchange/taler-exchange-httpd_deposit.c
index fd36bb4a0..23a97fb1b 100644
--- a/src/exchange/taler-exchange-httpd_deposit.c
+++ b/src/exchange/taler-exchange-httpd_deposit.c
@@ -29,7 +29,7 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include "taler_json_lib.h"
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_deposit.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_keystate.h"
@@ -83,17 +83,17 @@ reply_deposit_success (struct MHD_Connection *connection,
                    &pub,
                    &sig))
   {
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:s, s:o, s:o}",
-                                       "status", "DEPOSIT_OK",
-                                       "sig", GNUNET_JSON_from_data_auto (&sig),
-                                       "pub", GNUNET_JSON_from_data_auto (
-                                         &pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:s, s:o, s:o}",
+                                    "status", "DEPOSIT_OK",
+                                    "sig", GNUNET_JSON_from_data_auto (&sig),
+                                    "pub", GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -149,8 +149,10 @@ deposit_transaction (void *cls,
   {
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_DEPOSIT_HISTORY_DB_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_DEPOSIT_HISTORY_DB_ERROR,
+                                             "Could not check for existing identical deposit");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
     return qs;
@@ -197,8 +199,10 @@ deposit_transaction (void *cls,
   {
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_DEPOSIT_HISTORY_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_DEPOSIT_HISTORY_DB_ERROR,
+                                           "could not access coin history");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   /* Check that cost of all transactions is smaller than
@@ -223,8 +227,10 @@ deposit_transaction (void *cls,
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
   {
     TALER_LOG_WARNING ("Failed to store /deposit information in database\n");
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_DEPOSIT_STORE_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_DEPOSIT_STORE_DB_ERROR,
+                                           "Could not persist /deposit data");
   }
   return qs;
 }
@@ -273,9 +279,10 @@ verify_and_execute_deposit (struct MHD_Connection *connection,
                                   &deposit->coin.coin_pub.eddsa_pub))
   {
     TALER_LOG_WARNING ("Invalid signature on /deposit request\n");
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_DEPOSIT_COIN_SIGNATURE_INVALID,
-                                                 "coin_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_UNAUTHORIZED,
+                                       TALER_EC_DEPOSIT_COIN_SIGNATURE_INVALID,
+                                       "coin_sig");
   }
 
   /* check denomination */
@@ -283,9 +290,10 @@ verify_and_execute_deposit (struct MHD_Connection *connection,
   if (NULL == mks)
   {
     TALER_LOG_ERROR ("Lacking keys to operate\n");
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
   dki = TEH_KS_denomination_key_lookup_by_hash (mks,
                                                 &deposit->coin.denom_pub_hash,
@@ -295,9 +303,10 @@ verify_and_execute_deposit (struct MHD_Connection *connection,
   if (NULL == dki)
   {
     TEH_KS_release (mks);
-    return TEH_RESPONSE_reply_with_error (connection,
-                                          ec,
-                                          hc);
+    return TALER_MHD_reply_with_error (connection,
+                                       hc,
+                                       ec,
+                                       "Could not find denomination key used in deposit");
   }
   TALER_amount_ntoh (&dc.value,
                      &dki->issue.properties.value);
@@ -418,11 +427,11 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) ||
@@ -431,9 +440,9 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   memset (&deposit,
           0,
           sizeof (deposit));
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_SYSERR == res)
     return MHD_NO; /* hard failure */
@@ -445,9 +454,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   {
     GNUNET_break_op (0);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_DEPOSIT_REFUND_DEADLINE_AFTER_WIRE_DEADLINE,
-                                           "refund_deadline");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_DEPOSIT_REFUND_DEADLINE_AFTER_WIRE_DEADLINE,
+                                       "refund_deadline");
   }
 
   if (TALER_EC_NONE !=
@@ -455,9 +465,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
                                           &emsg)))
   {
     GNUNET_JSON_parse_free (spec);
-    res = TEH_RESPONSE_reply_external_error (connection,
-                                             ec,
-                                             emsg);
+    res = TALER_MHD_reply_with_error (connection,
+                                      MHD_HTTP_BAD_REQUEST,
+                                      ec,
+                                      emsg);
     GNUNET_free (emsg);
     return res;
   }
@@ -466,9 +477,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   {
     GNUNET_break_op (0);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_DEPOSIT_INVALID_TIMESTAMP,
-                                           "timestamp");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_DEPOSIT_INVALID_TIMESTAMP,
+                                       "timestamp");
   }
   if (GNUNET_OK !=
       TALER_JSON_merchant_wire_signature_hash (wire,
@@ -477,18 +489,20 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
     TALER_LOG_WARNING (
       "Failed to parse JSON wire format specification for /deposit request\n");
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_JSON,
-                                           "wire");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_JSON,
+                                       "wire");
   }
   if (0 != GNUNET_memcmp (&deposit.h_wire,
                           &my_h_wire))
   {
     /* Client hashed contract differently than we did, reject */
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_CONTRACT_HASH_CONFLICT,
-                                           "H_wire");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_CONTRACT_HASH_CONFLICT,
+                                       "H_wire");
   }
 
   /* check denomination exists and is valid */
@@ -497,9 +511,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   {
     TALER_LOG_ERROR ("Lacking keys to operate\n");
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
   dki = TEH_KS_denomination_key_lookup_by_hash (key_state,
                                                 &deposit.coin.denom_pub_hash,
@@ -511,9 +526,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
     TEH_KS_release (key_state);
     TALER_LOG_WARNING ("Unknown denomination key in /deposit request\n");
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_with_error (connection,
-                                          ec,
-                                          hc);
+    return TALER_MHD_reply_with_error (connection,
+                                       hc,
+                                       ec,
+                                       "Could not find denomination key used in deposit");
   }
   TALER_amount_ntoh (&deposit.deposit_fee,
                      &dki->issue.properties.fee_deposit);
@@ -525,9 +541,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
     TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
     TEH_KS_release (key_state);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_DEPOSIT_DENOMINATION_SIGNATURE_INVALID,
-                                                 "ub_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_UNAUTHORIZED,
+                                       TALER_EC_DEPOSIT_DENOMINATION_SIGNATURE_INVALID,
+                                       "ub_sig");
   }
   TALER_amount_ntoh (&deposit.deposit_fee,
                      &dki->issue.properties.fee_deposit);
@@ -538,9 +555,10 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   {
     GNUNET_break_op (0);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_external_error (connection,
-                                              TALER_EC_DEPOSIT_NEGATIVE_VALUE_AFTER_FEE,
-                                              "deposited amount smaller than depositing fee");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_DEPOSIT_NEGATIVE_VALUE_AFTER_FEE,
+                                       "deposited amount smaller than depositing fee");
   }
 
   /* make sure coin is 'known' in database */
diff --git a/src/exchange/taler-exchange-httpd_keystate.c b/src/exchange/taler-exchange-httpd_keystate.c
index bde5c7d7e..cf5cbe9a0 100644
--- a/src/exchange/taler-exchange-httpd_keystate.c
+++ b/src/exchange/taler-exchange-httpd_keystate.c
@@ -23,6 +23,7 @@
 #include "platform.h"
 #include <pthread.h>
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_keystate.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler_exchangedb_plugin.h"
@@ -1242,7 +1243,7 @@ setup_general_response_headers (const struct TEH_KS_StateHandle *key_state,
 {
   char dat[128];
 
-  TEH_RESPONSE_add_global_headers (response);
+  TALER_MHD_add_global_headers (response);
   GNUNET_break (MHD_YES ==
                 MHD_add_response_header (response,
                                          MHD_HTTP_HEADER_CONTENT_TYPE,
@@ -1545,8 +1546,8 @@ build_keys_response (const struct ResponseFactoryContext *rfc,
   }
 
   /* Also compute compressed version of /keys response */
-  comp = TEH_RESPONSE_body_compress (&keys_jsonz,
-                                     &keys_jsonz_size);
+  comp = TALER_MHD_body_compress (&keys_jsonz,
+                                  &keys_jsonz_size);
   krd->response_compressed
     = MHD_create_response_from_buffer (keys_jsonz_size,
                                        keys_jsonz,
@@ -2378,9 +2379,10 @@ TEH_KS_handler_keys (struct TEH_RequestHandler *rh,
                 &cherrypickn))
     {
       GNUNET_break_op (0);
-      return TEH_RESPONSE_reply_arg_invalid (connection,
-                                             TALER_EC_KEYS_HAVE_NOT_NUMERIC,
-                                             "last_issue_date");
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_BAD_REQUEST,
+                                         TALER_EC_KEYS_HAVE_NOT_NUMERIC,
+                                         "last_issue_date");
     }
     last_issue_date.abs_value_us = (uint64_t) cherrypickn * 1000000LLU;
   }
@@ -2402,9 +2404,10 @@ TEH_KS_handler_keys (struct TEH_RequestHandler *rh,
                 &fakenown))
     {
       GNUNET_break_op (0);
-      return TEH_RESPONSE_reply_arg_invalid (connection,
-                                             TALER_EC_KEYS_HAVE_NOT_NUMERIC,
-                                             "now");
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_BAD_REQUEST,
+                                         TALER_EC_KEYS_HAVE_NOT_NUMERIC,
+                                         "now");
     }
     now.abs_value_us = (uint64_t) fakenown * 1000000LLU;
   }
@@ -2413,9 +2416,10 @@ TEH_KS_handler_keys (struct TEH_RequestHandler *rh,
   if (NULL == key_state)
   {
     TALER_LOG_ERROR ("Lacking keys to operate\n");
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
   krd = bsearch (&last_issue_date,
                  key_state->krd_array,
@@ -2444,7 +2448,7 @@ TEH_KS_handler_keys (struct TEH_RequestHandler *rh,
   }
   ret = MHD_queue_response (connection,
                             rh->response_code,
-                            (MHD_YES == TEH_RESPONSE_can_compress (connection))
+                            (MHD_YES == TALER_MHD_can_compress (connection))
                             ? krd->response_compressed
                             : krd->response_uncompressed);
   TEH_KS_release (key_state);
diff --git a/src/exchange/taler-exchange-httpd_keystate.h b/src/exchange/taler-exchange-httpd_keystate.h
index 708b043b5..5d92af2b2 100644
--- a/src/exchange/taler-exchange-httpd_keystate.h
+++ b/src/exchange/taler-exchange-httpd_keystate.h
@@ -26,6 +26,7 @@
 #include <gnunet/gnunet_util_lib.h>
 #include <microhttpd.h>
 #include "taler-exchange-httpd.h"
+#include "taler_error_codes.h"
 #include "taler_exchangedb_lib.h"
 
 
diff --git a/src/exchange/taler-exchange-httpd_mhd.c b/src/exchange/taler-exchange-httpd_mhd.c
index 95e51c8ed..825a1b310 100644
--- a/src/exchange/taler-exchange-httpd_mhd.c
+++ b/src/exchange/taler-exchange-httpd_mhd.c
@@ -28,6 +28,7 @@
 #include <jansson.h>
 #include <microhttpd.h>
 #include <pthread.h>
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd.h"
 #include "taler-exchange-httpd_mhd.h"
@@ -66,7 +67,7 @@ TEH_MHD_handler_static_response (struct TEH_RequestHandler *rh,
     GNUNET_break (0);
     return MHD_NO;
   }
-  TEH_RESPONSE_add_global_headers (response);
+  TALER_MHD_add_global_headers (response);
   if (NULL != rh->mime_type)
     (void) MHD_add_response_header (response,
                                     MHD_HTTP_HEADER_CONTENT_TYPE,
@@ -97,41 +98,12 @@ TEH_MHD_handler_agpl_redirect (struct TEH_RequestHandler *rh,
                                const char *upload_data,
                                size_t *upload_data_size)
 {
-  const char *agpl =
-    "This server is licensed under the Affero GPL. You will now be redirected to the source code.";
-  struct MHD_Response *response;
-  int ret;
-
+  (void) rh;
   (void) connection_cls;
   (void) upload_data;
   (void) upload_data_size;
-  response = MHD_create_response_from_buffer (strlen (agpl),
-                                              (void *) agpl,
-                                              MHD_RESPMEM_PERSISTENT);
-  if (NULL == response)
-  {
-    GNUNET_break (0);
-    return MHD_NO;
-  }
-  TEH_RESPONSE_add_global_headers (response);
-  if (NULL != rh->mime_type)
-    (void) MHD_add_response_header (response,
-                                    MHD_HTTP_HEADER_CONTENT_TYPE,
-                                    rh->mime_type);
-  if (MHD_NO ==
-      MHD_add_response_header (response,
-                               MHD_HTTP_HEADER_LOCATION,
-                               "http://www.git.taler.net/?p=exchange.git"))
-  {
-    GNUNET_break (0);
-    MHD_destroy_response (response);
-    return MHD_NO;
-  }
-  ret = MHD_queue_response (connection,
-                            rh->response_code,
-                            response);
-  MHD_destroy_response (response);
-  return ret;
+  return TALER_MHD_reply_agpl (connection,
+                               "http://www.git.taler.net/?p=exchange.git");
 }
 
 
@@ -156,11 +128,11 @@ TEH_MHD_handler_send_json_pack_error (struct TEH_RequestHandler *rh,
   (void) connection_cls;
   (void) upload_data;
   (void) upload_data_size;
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       rh->response_code,
-                                       "{s:s}",
-                                       "error",
-                                       rh->data);
+  return TALER_MHD_reply_json_pack (connection,
+                                    rh->response_code,
+                                    "{s:s}",
+                                    "error",
+                                    rh->data);
 }
 
 
diff --git a/src/exchange/taler-exchange-httpd_parsing.h b/src/exchange/taler-exchange-httpd_parsing.h
deleted file mode 100644
index 9c5381756..000000000
--- a/src/exchange/taler-exchange-httpd_parsing.h
+++ /dev/null
@@ -1,139 +0,0 @@
-/*
-  This file is part of TALER
-  Copyright (C) 2014, 2015, 2016 GNUnet e.V.
-
-  TALER is free software; you can redistribute it and/or modify it under the
-  terms of the GNU Affero General Public License as published by the Free Software
-  Foundation; either version 3, or (at your option) any later version.
-
-  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
-
-  You should have received a copy of the GNU Affero General Public License along with
-  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
-*/
-/**
- * @file taler-exchange-httpd_parsing.h
- * @brief functions to parse incoming requests
- * @author Florian Dold
- * @author Benedikt Mueller
- * @author Christian Grothoff
- */
-#ifndef TALER_EXCHANGE_HTTPD_PARSING_H
-#define TALER_EXCHANGE_HTTPD_PARSING_H
-
-#include <microhttpd.h>
-#include <jansson.h>
-#include "taler_util.h"
-#include "taler_json_lib.h"
-
-
-/**
- * Process a POST request containing a JSON object.  This
- * function realizes an MHD POST processor that will
- * (incrementally) process JSON data uploaded to the HTTP
- * server.  It will store the required state in the
- * "connection_cls", which must be cleaned up using
- * #TEH_PARSE_post_cleanup_callback().
- *
- * @param connection the MHD connection
- * @param con_cls the closure (points to a `struct Buffer *`)
- * @param upload_data the POST data
- * @param upload_data_size number of bytes in @a upload_data
- * @param json the JSON object for a completed request
- * @return
- *    #GNUNET_YES if json object was parsed or at least
- *               may be parsed in the future (call again);
- *               `*json` will be NULL if we need to be called again,
- *                and non-NULL if we are done.
- *    #GNUNET_NO is request incomplete or invalid
- *               (error message was generated)
- *    #GNUNET_SYSERR on internal error
- *               (we could not even queue an error message,
- *                close HTTP session with MHD_NO)
- */
-int
-TEH_PARSE_post_json (struct MHD_Connection *connection,
-                     void **con_cls,
-                     const char *upload_data,
-                     size_t *upload_data_size,
-                     json_t **json);
-
-
-/**
- * Function called whenever we are done with a request
- * to clean up our state.
- *
- * @param con_cls value as it was left by
- *        #TEH_PARSE_post_json(), to be cleaned up
- */
-void
-TEH_PARSE_post_cleanup_callback (void *con_cls);
-
-
-/**
- * Parse JSON object into components based on the given field
- * specification.
- *
- * @param connection the connection to send an error response to
- * @param root the JSON node to start the navigation at.
- * @param spec field specification for the parser
- * @return
- *    #GNUNET_YES if navigation was successful (caller is responsible
- *                for freeing allocated variable-size data using
- *                GNUNET_JSON_parse_free() when done)
- *    #GNUNET_NO if json is malformed, error response was generated
- *    #GNUNET_SYSERR on internal error
- */
-int
-TEH_PARSE_json_data (struct MHD_Connection *connection,
-                     const json_t *root,
-                     struct GNUNET_JSON_Specification *spec);
-
-
-/**
- * Parse JSON array into components based on the given field
- * specification.  Generates error response on parse errors.
- *
- * @param connection the connection to send an error response to
- * @param root the JSON node to start the navigation at.
- * @param[in,out] spec field specification for the parser
- * @param ... -1-terminated list of array offsets of type 'int'
- * @return
- *    #GNUNET_YES if navigation was successful (caller is responsible
- *                for freeing allocated variable-size data using
- *                GNUNET_JSON_parse_free() when done)
- *    #GNUNET_NO if json is malformed, error response was generated
- *    #GNUNET_SYSERR on internal error
- */
-int
-TEH_PARSE_json_array (struct MHD_Connection *connection,
-                      const json_t *root,
-                      struct GNUNET_JSON_Specification *spec,
-                      ...);
-
-
-/**
- * Extraxt fixed-size base32crockford encoded data from request.
- *
- * Queues an error response to the connection if the parameter is missing or
- * invalid.
- *
- * @param connection the MHD connection
- * @param param_name the name of the parameter with the key
- * @param[out] out_data pointer to store the result
- * @param out_size expected size of @a out_data
- * @return
- *   #GNUNET_YES if the the argument is present
- *   #GNUNET_NO if the argument is absent or malformed
- *   #GNUNET_SYSERR on internal error (error response could not be sent)
- */
-int
-TEH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
-                                const char *param_name,
-                                void *out_data,
-                                size_t out_size);
-
-
-#endif /* TALER_EXCHANGE_HTTPD_PARSING_H */
diff --git a/src/exchange/taler-exchange-httpd_payback.c b/src/exchange/taler-exchange-httpd_payback.c
index 05a2355a3..b7fe593d9 100644
--- a/src/exchange/taler-exchange-httpd_payback.c
+++ b/src/exchange/taler-exchange-httpd_payback.c
@@ -27,7 +27,7 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include "taler_json_lib.h"
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_payback.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_keystate.h"
@@ -35,26 +35,6 @@
 
 
 /**
- * A wallet asked for /payback, but we do not know anything about the
- * original withdraw operation specified. Generates a 404 reply.
- *
- * @param connection connection to the client
- * @param ec Taler error code
- * @return MHD result code
- */
-static int
-reply_payback_unknown (struct MHD_Connection *connection,
-                       enum TALER_ErrorCode ec)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_NOT_FOUND,
-                                       "{s:s, s:I}",
-                                       "error", "blinded coin unknown",
-                                       "code", (json_int_t) ec);
-}
-
-
-/**
  * A wallet asked for /payback, return the successful response.
  *
  * @param connection connection to the client
@@ -88,24 +68,25 @@ reply_payback_refresh_success (struct MHD_Connection *connection,
                    &pub,
                    &sig))
   {
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o, s:o, s:o, s:o, s:o}",
-                                       "old_coin_pub",
-                                       GNUNET_JSON_from_data_auto (
-                                         old_coin_pub),
-                                       "timestamp", GNUNET_JSON_from_time_abs (
-                                         timestamp),
-                                       "amount", TALER_JSON_from_amount (
-                                         amount),
-                                       "exchange_sig",
-                                       GNUNET_JSON_from_data_auto (&sig),
-                                       "exchange_pub",
-                                       GNUNET_JSON_from_data_auto (&pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o, s:o, s:o, s:o, s:o}",
+                                    "old_coin_pub",
+                                    GNUNET_JSON_from_data_auto (
+                                      old_coin_pub),
+                                    "timestamp", GNUNET_JSON_from_time_abs (
+                                      timestamp),
+                                    "amount", TALER_JSON_from_amount (
+                                      amount),
+                                    "exchange_sig",
+                                    GNUNET_JSON_from_data_auto (&sig),
+                                    "exchange_pub",
+                                    GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -142,23 +123,24 @@ reply_payback_success (struct MHD_Connection *connection,
                    &pub,
                    &sig))
   {
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o, s:o, s:o, s:o, s:o}",
-                                       "reserve_pub",
-                                       GNUNET_JSON_from_data_auto (reserve_pub),
-                                       "timestamp", GNUNET_JSON_from_time_abs (
-                                         timestamp),
-                                       "amount", TALER_JSON_from_amount (
-                                         amount),
-                                       "exchange_sig",
-                                       GNUNET_JSON_from_data_auto (&sig),
-                                       "exchange_pub",
-                                       GNUNET_JSON_from_data_auto (&pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o, s:o, s:o, s:o, s:o}",
+                                    "reserve_pub",
+                                    GNUNET_JSON_from_data_auto (reserve_pub),
+                                    "timestamp", GNUNET_JSON_from_time_abs (
+                                      timestamp),
+                                    "amount", TALER_JSON_from_amount (
+                                      amount),
+                                    "exchange_sig",
+                                    GNUNET_JSON_from_data_auto (&sig),
+                                    "exchange_pub",
+                                    GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -268,8 +250,10 @@ payback_transaction (void *cls,
       if (GNUNET_DB_STATUS_HARD_ERROR == qs)
       {
         GNUNET_break (0);
-        *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                         TALER_EC_PAYBACK_DB_FETCH_FAILED);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_PAYBACK_DB_FETCH_FAILED,
+                                               "failed to fetch old coin of blind coin");
       }
       return qs;
     }
@@ -285,8 +269,10 @@ payback_transaction (void *cls,
       if (GNUNET_DB_STATUS_HARD_ERROR == qs)
       {
         GNUNET_break (0);
-        *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                         TALER_EC_PAYBACK_DB_FETCH_FAILED);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_PAYBACK_DB_FETCH_FAILED,
+                                               "failed to fetch reserve of blinded coin");
       }
       return qs;
     }
@@ -296,8 +282,10 @@ payback_transaction (void *cls,
     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                 "Payback requested for unknown envelope %s\n",
                 GNUNET_h2s (&pc->h_blind));
-    *mhd_ret = reply_payback_unknown (connection,
-                                      TALER_EC_PAYBACK_WITHDRAW_NOT_FOUND);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_PAYBACK_WITHDRAW_NOT_FOUND,
+                                           "blind coin unknown");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
 
@@ -312,8 +300,10 @@ payback_transaction (void *cls,
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
       GNUNET_break (0);
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_PAYBACK_DB_FETCH_FAILED);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_PAYBACK_DB_FETCH_FAILED,
+                                             "failed to fetch old coin transaction history");
     }
     return qs;
   }
@@ -329,8 +319,10 @@ payback_transaction (void *cls,
     GNUNET_break (0);
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_PAYBACK_HISTORY_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_PAYBACK_HISTORY_DB_ERROR,
+                                           "failed to calculate old coin transaction history");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if (GNUNET_SYSERR ==
@@ -341,8 +333,10 @@ payback_transaction (void *cls,
     GNUNET_break (0);
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_PAYBACK_COIN_BALANCE_NEGATIVE);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_PAYBACK_COIN_BALANCE_NEGATIVE,
+                                           "calculated negative old coin balance");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if ( (0 == pc->amount.fraction) &&
@@ -391,8 +385,10 @@ payback_transaction (void *cls,
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
       TALER_LOG_WARNING ("Failed to store /payback information in database\n");
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_PAYBACK_DB_PUT_FAILED);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_PAYBACK_DB_PUT_FAILED,
+                                             "failed to persist payback data");
     }
     return qs;
   }
@@ -437,9 +433,10 @@ verify_and_execute_payback (struct MHD_Connection *connection,
   if (NULL == key_state)
   {
     TALER_LOG_ERROR ("Lacking keys to operate\n");
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
   dki = TEH_KS_denomination_key_lookup_by_hash (key_state,
                                                 &coin->denom_pub_hash,
@@ -451,9 +448,10 @@ verify_and_execute_payback (struct MHD_Connection *connection,
     TEH_KS_release (key_state);
     TALER_LOG_WARNING (
       "Denomination key in /payback request not in payback mode\n");
-    return TEH_RESPONSE_reply_with_error (connection,
-                                          ec,
-                                          hc);
+    return TALER_MHD_reply_with_error (connection,
+                                       hc,
+                                       ec,
+                                       "denomination not allowing payback");
   }
   TALER_amount_ntoh (&pc.value,
                      &dki->issue.properties.value);
@@ -465,9 +463,10 @@ verify_and_execute_payback (struct MHD_Connection *connection,
   {
     TALER_LOG_WARNING ("Invalid coin passed for /payback\n");
     TEH_KS_release (key_state);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_PAYBACK_DENOMINATION_SIGNATURE_INVALID,
-                                                 "denom_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_PAYBACK_DENOMINATION_SIGNATURE_INVALID,
+                                       "denom_sig");
   }
 
   /* check payback request signature */
@@ -485,9 +484,10 @@ verify_and_execute_payback (struct MHD_Connection *connection,
   {
     TALER_LOG_WARNING ("Invalid signature on /payback request\n");
     TEH_KS_release (key_state);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_PAYBACK_SIGNATURE_INVALID,
-                                                 "coin_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_PAYBACK_SIGNATURE_INVALID,
+                                       "coin_sig");
   }
 
   GNUNET_CRYPTO_hash (&coin->coin_pub.eddsa_pub,
@@ -503,9 +503,10 @@ verify_and_execute_payback (struct MHD_Connection *connection,
     GNUNET_break (0);
     TEH_KS_release (key_state);
 
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_PAYBACK_BLINDING_FAILED,
-                                              "coin_bks");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_PAYBACK_BLINDING_FAILED,
+                                       "coin_bks");
   }
   TEH_KS_release (key_state);
   GNUNET_CRYPTO_hash (coin_ev,
@@ -603,18 +604,18 @@ TEH_PAYBACK_handler_payback (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_SYSERR == res)
     return MHD_NO; /* hard failure */
diff --git a/src/exchange/taler-exchange-httpd_refresh_link.c b/src/exchange/taler-exchange-httpd_refresh_link.c
index c51887a95..c3d36e29b 100644
--- a/src/exchange/taler-exchange-httpd_refresh_link.c
+++ b/src/exchange/taler-exchange-httpd_refresh_link.c
@@ -24,7 +24,7 @@
 #include <gnunet/gnunet_util_lib.h>
 #include <jansson.h>
 #include <microhttpd.h>
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_mhd.h"
 #include "taler-exchange-httpd_refresh_link.h"
 #include "taler-exchange-httpd_responses.h"
@@ -156,16 +156,18 @@ refresh_link_transaction (void *cls,
                                   ctx);
   if (NULL == ctx->mlist)
   {
-    *mhd_ret = TEH_RESPONSE_reply_internal_error (connection,
-                                                  ctx->ec,
-                                                  "coin_pub");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           ctx->ec,
+                                           "coin_pub");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
   {
-    *mhd_ret = TEH_RESPONSE_reply_arg_unknown (connection,
-                                               TALER_EC_REFRESH_LINK_COIN_UNKNOWN,
-                                               "coin_pub");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_REFRESH_LINK_COIN_UNKNOWN,
+                                           "coin_pub");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   return qs;
@@ -201,11 +203,11 @@ TEH_REFRESH_handler_refresh_link (struct TEH_RequestHandler *rh,
   memset (&ctx,
           0,
           sizeof (ctx));
-  res = TEH_PARSE_mhd_request_arg_data (connection,
-                                        "coin_pub",
-                                        &ctx.coin_pub,
-                                        sizeof (struct
-                                                TALER_CoinSpendPublicKeyP));
+  res = TALER_MHD_parse_request_arg_data (connection,
+                                          "coin_pub",
+                                          &ctx.coin_pub,
+                                          sizeof (struct
+                                                  TALER_CoinSpendPublicKeyP));
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if (GNUNET_OK != res)
@@ -222,9 +224,9 @@ TEH_REFRESH_handler_refresh_link (struct TEH_RequestHandler *rh,
       json_decref (ctx.mlist);
     return mhd_ret;
   }
-  mhd_ret = TEH_RESPONSE_reply_json (connection,
-                                     ctx.mlist,
-                                     MHD_HTTP_OK);
+  mhd_ret = TALER_MHD_reply_json (connection,
+                                  ctx.mlist,
+                                  MHD_HTTP_OK);
   json_decref (ctx.mlist);
   return mhd_ret;
 }
diff --git a/src/exchange/taler-exchange-httpd_refresh_melt.c b/src/exchange/taler-exchange-httpd_refresh_melt.c
index a00fda14f..8fbb58513 100644
--- a/src/exchange/taler-exchange-httpd_refresh_melt.c
+++ b/src/exchange/taler-exchange-httpd_refresh_melt.c
@@ -24,7 +24,8 @@
 #include <gnunet/gnunet_util_lib.h>
 #include <jansson.h>
 #include <microhttpd.h>
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_mhd.h"
 #include "taler-exchange-httpd_refresh_melt.h"
 #include "taler-exchange-httpd_responses.h"
@@ -60,26 +61,28 @@ reply_refresh_melt_insufficient_funds (struct MHD_Connection *connection,
 
   history = TEH_RESPONSE_compile_transaction_history (tl);
   if (NULL == history)
-    return TEH_RESPONSE_reply_internal_db_error (connection,
-                                                 TALER_EC_REFRESH_MELT_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_FORBIDDEN,
-                                       "{s:s, s:I, s:o, s:o, s:o, s:o, s:o}",
-                                       "error",
-                                       "insufficient funds",
-                                       "code",
-                                       (json_int_t)
-                                       TALER_EC_REFRESH_MELT_INSUFFICIENT_FUNDS,
-                                       "coin_pub",
-                                       GNUNET_JSON_from_data_auto (coin_pub),
-                                       "original_value",
-                                       TALER_JSON_from_amount (&coin_value),
-                                       "residual_value",
-                                       TALER_JSON_from_amount (residual),
-                                       "requested_value",
-                                       TALER_JSON_from_amount (requested),
-                                       "history",
-                                       history);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_REFRESH_MELT_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS,
+                                       "Failed to compile transaction history");
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_CONFLICT,
+                                    "{s:s, s:I, s:o, s:o, s:o, s:o, s:o}",
+                                    "error",
+                                    "insufficient funds",
+                                    "code",
+                                    (json_int_t)
+                                    TALER_EC_REFRESH_MELT_INSUFFICIENT_FUNDS,
+                                    "coin_pub",
+                                    GNUNET_JSON_from_data_auto (coin_pub),
+                                    "original_value",
+                                    TALER_JSON_from_amount (&coin_value),
+                                    "residual_value",
+                                    TALER_JSON_from_amount (residual),
+                                    "requested_value",
+                                    TALER_JSON_from_amount (requested),
+                                    "history",
+                                    history);
 }
 
 
@@ -110,19 +113,20 @@ reply_refresh_melt_success (struct MHD_Connection *connection,
                    &pub,
                    &sig))
   {
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
   sig_json = GNUNET_JSON_from_data_auto (&sig);
   GNUNET_assert (NULL != sig_json);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:i, s:o, s:o}",
-                                       "noreveal_index", (int) noreveal_index,
-                                       "exchange_sig", sig_json,
-                                       "exchange_pub",
-                                       GNUNET_JSON_from_data_auto (&pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:i, s:o, s:o}",
+                                    "noreveal_index", (int) noreveal_index,
+                                    "exchange_sig", sig_json,
+                                    "exchange_pub",
+                                    GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -189,8 +193,10 @@ refresh_check_melt (struct MHD_Connection *connection,
   if (0 > qs)
   {
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_REFRESH_MELT_DB_FETCH_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_REFRESH_MELT_DB_FETCH_ERROR,
+                                             "failed to fetch old coin history");
     return qs;
   }
   if (rmc->zombie_required)
@@ -211,9 +217,10 @@ refresh_check_melt (struct MHD_Connection *connection,
       GNUNET_break (0);
       TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                               tl);
-      *mhd_ret = TEH_RESPONSE_reply_external_error (connection,
-                                                    TALER_EC_REFRESH_MELT_COIN_EXPIRED_NO_ZOMBIE,
-                                                    "denomination expired");
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_BAD_REQUEST,
+                                             TALER_EC_REFRESH_MELT_COIN_EXPIRED_NO_ZOMBIE,
+                                             "denomination expired");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
   }
@@ -225,8 +232,10 @@ refresh_check_melt (struct MHD_Connection *connection,
     GNUNET_break (0);
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_REFRESH_MELT_COIN_HISTORY_COMPUTATION_FAILED);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_REFRESH_MELT_COIN_HISTORY_COMPUTATION_FAILED,
+                                           "failed to compute coin transaction history");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
 
@@ -310,8 +319,10 @@ refresh_melt_transaction (void *cls,
   if (0 > qs)
   {
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_REFRESH_MELT_DB_FETCH_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_REFRESH_MELT_DB_FETCH_ERROR,
+                                             "failed to fetch melt index");
     return qs;
   }
 
@@ -335,8 +346,10 @@ refresh_melt_transaction (void *cls,
   {
     if (GNUNET_DB_STATUS_SOFT_ERROR != qs)
     {
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_REFRESH_MELT_DB_STORE_SESSION_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_REFRESH_MELT_DB_STORE_SESSION_ERROR,
+                                             "failed to persist melt data");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
     return qs;
@@ -370,9 +383,10 @@ handle_refresh_melt (struct MHD_Connection *connection,
                           &rmc->refresh_session.amount_with_fee) > 0)
     {
       GNUNET_break_op (0);
-      return TEH_RESPONSE_reply_external_error (connection,
-                                                TALER_EC_REFRESH_MELT_FEES_EXCEED_CONTRIBUTION,
-                                                "melt amount smaller than melting fee");
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_BAD_REQUEST,
+                                         TALER_EC_REFRESH_MELT_FEES_EXCEED_CONTRIBUTION,
+                                         "melt amount smaller than melting fee");
     }
   }
 
@@ -398,9 +412,10 @@ handle_refresh_melt (struct MHD_Connection *connection,
                                     eddsa_pub))
     {
       GNUNET_break_op (0);
-      return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                   TALER_EC_REFRESH_MELT_COIN_SIGNATURE_INVALID,
-                                                   "confirm_sig");
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_FORBIDDEN,
+                                         TALER_EC_REFRESH_MELT_COIN_SIGNATURE_INVALID,
+                                         "confirm_sig");
     }
   }
 
@@ -467,11 +482,11 @@ TEH_REFRESH_handler_refresh_melt (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &root);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &root);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) ||
@@ -481,9 +496,9 @@ TEH_REFRESH_handler_refresh_melt (struct TEH_RequestHandler *rh,
   memset (&rmc,
           0,
           sizeof (rmc));
-  res = TEH_PARSE_json_data (connection,
-                             root,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   root,
+                                   spec);
   json_decref (root);
   if (GNUNET_OK != res)
     return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
@@ -492,9 +507,10 @@ TEH_REFRESH_handler_refresh_melt (struct TEH_RequestHandler *rh,
   if (NULL == key_state)
   {
     TALER_LOG_ERROR ("Lacking keys to operate\n");
-    res = TEH_RESPONSE_reply_internal_error (connection,
-                                             TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                             "no keys");
+    res = TALER_MHD_reply_with_error (connection,
+                                      MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                      TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                      "no keys");
     goto cleanup;
   }
 
@@ -530,8 +546,10 @@ TEH_REFRESH_handler_refresh_melt (struct TEH_RequestHandler *rh,
       if (0 > qs)
       {
         GNUNET_break (0);
-        res = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                    TALER_EC_REFRESH_MELT_DB_FETCH_ERROR);
+        res = TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                          TALER_EC_REFRESH_MELT_DB_FETCH_ERROR,
+                                          "failed to find information about old coin");
         goto cleanup;
       }
       if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs)
@@ -566,9 +584,10 @@ TEH_REFRESH_handler_refresh_melt (struct TEH_RequestHandler *rh,
   if (NULL == rmc.dki)
   {
     TALER_LOG_WARNING ("Unknown denomination key in /refresh/melt request\n");
-    res = TEH_RESPONSE_reply_with_error (connection,
-                                         ec,
-                                         hc);
+    res = TALER_MHD_reply_with_error (connection,
+                                      hc,
+                                      ec,
+                                      "unknown denomination");
     goto cleanup;
   }
 
@@ -579,9 +598,10 @@ TEH_REFRESH_handler_refresh_melt (struct TEH_RequestHandler *rh,
     GNUNET_break_op (0);
     GNUNET_JSON_parse_free (spec);
     TEH_KS_release (key_state);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_REFRESH_MELT_DENOMINATION_SIGNATURE_INVALID,
-                                                 "denom_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_REFRESH_MELT_DENOMINATION_SIGNATURE_INVALID,
+                                       "denom_sig");
   }
 
   /* run actual logic, now that the request was parsed */
diff --git a/src/exchange/taler-exchange-httpd_refresh_reveal.c b/src/exchange/taler-exchange-httpd_refresh_reveal.c
index be5228dd9..fb2602c61 100644
--- a/src/exchange/taler-exchange-httpd_refresh_reveal.c
+++ b/src/exchange/taler-exchange-httpd_refresh_reveal.c
@@ -24,7 +24,7 @@
 #include <gnunet/gnunet_util_lib.h>
 #include <jansson.h>
 #include <microhttpd.h>
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_mhd.h"
 #include "taler-exchange-httpd_refresh_reveal.h"
 #include "taler-exchange-httpd_responses.h"
@@ -84,9 +84,9 @@ reply_refresh_reveal_success (struct MHD_Connection *connection,
     json_object_set_new (root,
                          "ev_sigs",
                          list);
-    ret = TEH_RESPONSE_reply_json (connection,
-                                   root,
-                                   MHD_HTTP_OK);
+    ret = TALER_MHD_reply_json (connection,
+                                root,
+                                MHD_HTTP_OK);
     json_decref (root);
   }
   return ret;
@@ -105,15 +105,15 @@ static int
 reply_refresh_reveal_missmatch (struct MHD_Connection *connection,
                                 const struct TALER_RefreshCommitmentP *rc)
 {
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_CONFLICT,
-                                       "{s:s, s:I, s:o}",
-                                       "error", "commitment violation",
-                                       "code",
-                                       (json_int_t)
-                                       TALER_EC_REFRESH_REVEAL_COMMITMENT_VIOLATION,
-                                       "rc_expected",
-                                       GNUNET_JSON_from_data_auto (rc));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_CONFLICT,
+                                    "{s:s, s:I, s:o}",
+                                    "error", "commitment violation",
+                                    "code",
+                                    (json_int_t)
+                                    TALER_EC_REFRESH_REVEAL_COMMITMENT_VIOLATION,
+                                    "rc_expected",
+                                    GNUNET_JSON_from_data_auto (rc));
 }
 
 
@@ -258,8 +258,10 @@ refresh_reveal_preflight (void *cls,
     return qs;
   case GNUNET_DB_STATUS_HARD_ERROR:
     GNUNET_break (qs);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_REFRESH_REVEAL_DB_FETCH_REVEAL_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_REFRESH_REVEAL_DB_FETCH_REVEAL_ERROR,
+                                           "failed to fetch reveal data");
     rctx->preflight_ok = GNUNET_SYSERR;
     return GNUNET_DB_STATUS_HARD_ERROR;
   case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
@@ -308,9 +310,10 @@ refresh_reveal_transaction (void *cls,
                              &refresh_melt);
   if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
   {
-    *mhd_ret = TEH_RESPONSE_reply_arg_invalid (connection,
-                                               TALER_EC_REFRESH_REVEAL_SESSION_UNKNOWN,
-                                               "rc");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_REFRESH_REVEAL_SESSION_UNKNOWN,
+                                           "rc");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
@@ -319,8 +322,10 @@ refresh_reveal_transaction (void *cls,
        (refresh_melt.session.noreveal_index >= TALER_CNC_KAPPA) )
   {
     GNUNET_break (0);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_REFRESH_REVEAL_DB_FETCH_SESSION_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_REFRESH_REVEAL_DB_FETCH_SESSION_ERROR,
+                                           "failed to fetch valid challenge from database");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
 
@@ -437,9 +442,10 @@ refresh_reveal_transaction (void *cls,
                               &total)) )
       {
         GNUNET_break_op (0);
-        *mhd_ret = TEH_RESPONSE_reply_internal_error (connection,
-                                                      TALER_EC_REFRESH_REVEAL_COST_CALCULATION_OVERFLOW,
-                                                      "failed to add up refresh costs");
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_REFRESH_REVEAL_COST_CALCULATION_OVERFLOW,
+                                               "failed to add up refresh costs");
         return GNUNET_DB_STATUS_HARD_ERROR;
       }
     }
@@ -447,9 +453,10 @@ refresh_reveal_transaction (void *cls,
                               &refresh_melt.session.amount_with_fee))
     {
       GNUNET_break_op (0);
-      *mhd_ret = TEH_RESPONSE_reply_external_error (connection,
-                                                    TALER_EC_REFRESH_REVEAL_AMOUNT_INSUFFICIENT,
-                                                    "melted coin value is insufficient to cover cost of operation");
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_REFRESH_REVEAL_AMOUNT_INSUFFICIENT,
+                                             "melted coin value is insufficient to cover cost of operation");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
   }
@@ -501,8 +508,10 @@ refresh_reveal_persist (void *cls,
   }
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
   {
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_REFRESH_REVEAL_DB_COMMIT_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_REFRESH_REVEAL_DB_COMMIT_ERROR,
+                                           "failed to persist reveal data");
   }
   return qs;
 }
@@ -542,26 +551,29 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
        (0 == num_fresh_coins) )
   {
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_EXCESSIVE,
-                                           "new_denoms_h");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_EXCESSIVE,
+                                       "new_denoms_h");
 
   }
   if (json_array_size (new_denoms_h_json) !=
       json_array_size (coin_evs))
   {
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_MISSMATCH,
-                                           "new_denoms/coin_evs");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_MISSMATCH,
+                                       "new_denoms/coin_evs");
   }
   if (json_array_size (new_denoms_h_json) !=
       json_array_size (link_sigs_json))
   {
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_MISSMATCH,
-                                           "new_denoms/link_sigs");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_REFRESH_REVEAL_NEW_DENOMS_ARRAY_SIZE_MISSMATCH,
+                                       "new_denoms/link_sigs");
   }
 
   /* Parse transfer private keys array */
@@ -573,11 +585,11 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
     };
     int res;
 
-    res = TEH_PARSE_json_array (connection,
-                                tp_json,
-                                trans_spec,
-                                i,
-                                -1);
+    res = TALER_MHD_parse_json_array (connection,
+                                      tp_json,
+                                      trans_spec,
+                                      i,
+                                      -1);
     if (GNUNET_OK != res)
       return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
   }
@@ -597,9 +609,10 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
     {
       TALER_LOG_ERROR ("Lacking keys to operate\n");
       /* FIXME: use correct EC code! */
-      return TEH_RESPONSE_reply_internal_error (connection,
-                                                TALER_EC_REFRESH_REVEAL_SIGNING_ERROR,
-                                                "exchange lacks keys");
+      return TALER_MHD_reply_with_error (connection,
+                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                         TALER_EC_REFRESH_REVEAL_SIGNING_ERROR,
+                                         "exchange lacks keys");
     }
 
     /* Parse denomination key hashes */
@@ -613,11 +626,11 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
       unsigned int hc;
       enum TALER_ErrorCode ec;
 
-      res = TEH_PARSE_json_array (connection,
-                                  new_denoms_h_json,
-                                  spec,
-                                  i,
-                                  -1);
+      res = TALER_MHD_parse_json_array (connection,
+                                        new_denoms_h_json,
+                                        spec,
+                                        i,
+                                        -1);
       if (GNUNET_OK != res)
       {
         TEH_KS_release (key_state);
@@ -631,9 +644,10 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
       if (NULL == dkis[i])
       {
         TEH_KS_release (key_state);
-        return TEH_RESPONSE_reply_with_error (connection,
-                                              ec,
-                                              hc);
+        return TALER_MHD_reply_with_error (connection,
+                                           hc,
+                                           ec,
+                                           "failed to find denomination key");
       }
       GNUNET_assert (NULL != dkis[i]->denom_priv.rsa_private_key);
     }
@@ -649,11 +663,11 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
         GNUNET_JSON_spec_end ()
       };
 
-      res = TEH_PARSE_json_array (connection,
-                                  coin_evs,
-                                  spec,
-                                  i,
-                                  -1);
+      res = TALER_MHD_parse_json_array (connection,
+                                        coin_evs,
+                                        spec,
+                                        i,
+                                        -1);
       if (GNUNET_OK != res)
       {
         for (unsigned int j = 0; j<i; j++)
@@ -677,19 +691,24 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
         switch (qs)
         {
         case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
-          res = TEH_RESPONSE_reply_arg_invalid (connection,
-                                                TALER_EC_REFRESH_REVEAL_SESSION_UNKNOWN,
-                                                "rc");
+          res = TALER_MHD_reply_with_error (connection,
+                                            MHD_HTTP_NOT_FOUND,
+                                            TALER_EC_REFRESH_REVEAL_SESSION_UNKNOWN,
+                                            "rc");
           break;
         case GNUNET_DB_STATUS_HARD_ERROR:
-          res = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                      TALER_EC_REFRESH_REVEAL_DB_FETCH_SESSION_ERROR);
+          res = TALER_MHD_reply_with_error (connection,
+                                            MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                            TALER_EC_REFRESH_REVEAL_DB_FETCH_SESSION_ERROR,
+                                            "failed to fetch session data");
           break;
         case GNUNET_DB_STATUS_SOFT_ERROR:
         default:
           GNUNET_break (0); /* should be impossible */
-          res = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                      TALER_EC_INTERNAL_INVARIANT_FAILURE);
+          res = TALER_MHD_reply_with_error (connection,
+                                            MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                            TALER_EC_INTERNAL_INVARIANT_FAILURE,
+                                            "assertion failed");
           break;
         }
         goto cleanup;
@@ -704,11 +723,11 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
       };
       int res;
 
-      res = TEH_PARSE_json_array (connection,
-                                  link_sigs_json,
-                                  link_spec,
-                                  i,
-                                  -1);
+      res = TALER_MHD_parse_json_array (connection,
+                                        link_sigs_json,
+                                        link_spec,
+                                        i,
+                                        -1);
       if (GNUNET_OK != res)
         return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
       /* Check link_sigs[i] signature */
@@ -731,9 +750,10 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
                                         eddsa_pub))
         {
           GNUNET_break_op (0);
-          res = TEH_RESPONSE_reply_signature_invalid (connection,
-                                                      TALER_EC_REFRESH_REVEAL_LINK_SIGNATURE_INVALID,
-                                                      "link_sig");
+          res = TALER_MHD_reply_with_error (connection,
+                                            MHD_HTTP_FORBIDDEN,
+                                            TALER_EC_REFRESH_REVEAL_LINK_SIGNATURE_INVALID,
+                                            "link_sig");
           goto cleanup;
         }
       }
@@ -757,8 +777,10 @@ handle_refresh_reveal_json (struct MHD_Connection *connection,
       if (NULL == rctx->ev_sigs[i].rsa_signature)
       {
         GNUNET_break (0);
-        res = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                    TALER_EC_REFRESH_REVEAL_SIGNING_ERROR);
+        res = TALER_MHD_reply_with_error (connection,
+                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                          TALER_EC_REFRESH_REVEAL_SIGNING_ERROR,
+                                          "internal signing error");
         goto cleanup;
       }
     }
@@ -879,11 +901,11 @@ TEH_REFRESH_handler_refresh_reveal (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &root);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &root);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) ||
@@ -893,9 +915,9 @@ TEH_REFRESH_handler_refresh_reveal (struct TEH_RequestHandler *rh,
   memset (&rctx,
           0,
           sizeof (rctx));
-  res = TEH_PARSE_json_data (connection,
-                             root,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   root,
+                                   spec);
   json_decref (root);
   if (GNUNET_OK != res)
   {
@@ -909,9 +931,10 @@ TEH_REFRESH_handler_refresh_reveal (struct TEH_RequestHandler *rh,
   {
     GNUNET_JSON_parse_free (spec);
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_REFRESH_REVEAL_CNC_TRANSFER_ARRAY_SIZE_INVALID,
-                                           "transfer_privs");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_REFRESH_REVEAL_CNC_TRANSFER_ARRAY_SIZE_INVALID,
+                                       "transfer_privs");
   }
   res = handle_refresh_reveal_json (connection,
                                     &rctx,
diff --git a/src/exchange/taler-exchange-httpd_refund.c b/src/exchange/taler-exchange-httpd_refund.c
index 48532a2ce..6a96ff982 100644
--- a/src/exchange/taler-exchange-httpd_refund.c
+++ b/src/exchange/taler-exchange-httpd_refund.c
@@ -29,7 +29,7 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include "taler_json_lib.h"
-#include "taler-exchange-httpd_parsing.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_refund.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_keystate.h"
@@ -66,17 +66,17 @@ reply_refund_success (struct MHD_Connection *connection,
                    &pub,
                    &sig))
   {
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:s, s:o, s:o}",
-                                       "status", "REFUND_OK",
-                                       "sig", GNUNET_JSON_from_data_auto (&sig),
-                                       "pub", GNUNET_JSON_from_data_auto (
-                                         &pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:s, s:o, s:o}",
+                                    "status", "REFUND_OK",
+                                    "sig", GNUNET_JSON_from_data_auto (&sig),
+                                    "pub", GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -94,11 +94,11 @@ reply_refund_failure (struct MHD_Connection *connection,
                       unsigned int response_code,
                       enum TALER_ErrorCode ec)
 {
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       response_code,
-                                       "{s:s, s:I}",
-                                       "status", "refund failure",
-                                       "code", (json_int_t) ec);
+  return TALER_MHD_reply_json_pack (connection,
+                                    response_code,
+                                    "{s:s, s:I}",
+                                    "hint", "refund failure",
+                                    "code", (json_int_t) ec);
 }
 
 
@@ -114,15 +114,15 @@ static int
 reply_refund_conflict (struct MHD_Connection *connection,
                        const struct TALER_EXCHANGEDB_TransactionList *tl)
 {
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_CONFLICT,
-                                       "{s:s, s:I, s:o}",
-                                       "status", "conflicting refund",
-                                       "code",
-                                       (json_int_t) TALER_EC_REFUND_CONFLICT,
-                                       "history",
-                                       TEH_RESPONSE_compile_transaction_history (
-                                         tl));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_CONFLICT,
+                                    "{s:s, s:I, s:o}",
+                                    "hint", "conflicting refund",
+                                    "code",
+                                    (json_int_t) TALER_EC_REFUND_CONFLICT,
+                                    "history",
+                                    TEH_RESPONSE_compile_transaction_history (
+                                      tl));
 }
 
 
@@ -259,8 +259,10 @@ refund_transaction (void *cls,
     TALER_LOG_WARNING ("Deposit to /refund was not found\n");
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_transaction_unknown (connection,
-                                                       TALER_EC_REFUND_DEPOSIT_NOT_FOUND);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_REFUND_DEPOSIT_NOT_FOUND,
+                                           "deposit unknown");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   /* handle if conflicting refund found */
@@ -309,9 +311,10 @@ refund_transaction (void *cls,
     GNUNET_break (0);
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_internal_error (connection,
-                                                  TALER_EC_REFUND_DB_INCONSISTENT,
-                                                  "database inconsistent");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_REFUND_DB_INCONSISTENT,
+                                           "database inconsistent");
     return qs;
   }
   if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
@@ -349,9 +352,10 @@ refund_transaction (void *cls,
     TALER_LOG_ERROR ("Lacking keys to operate\n");
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_internal_error (connection,
-                                                  TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                                  "no keys");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                           "no keys");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   dki = TEH_KS_denomination_key_lookup_by_hash (mks,
@@ -367,9 +371,10 @@ refund_transaction (void *cls,
     TEH_KS_release (mks);
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_with_error (connection,
-                                              ec,
-                                              hc);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           hc,
+                                           ec,
+                                           "denomination not found, but coin known");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   TALER_amount_ntoh (&expect_fee,
@@ -382,9 +387,10 @@ refund_transaction (void *cls,
   {
     TEH_plugin->free_coin_transaction_list (TEH_plugin->cls,
                                             tl);
-    *mhd_ret = TEH_RESPONSE_reply_arg_invalid (connection,
-                                               TALER_EC_REFUND_FEE_TOO_LOW,
-                                               "refund_fee");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_BAD_REQUEST,
+                                           TALER_EC_REFUND_FEE_TOO_LOW,
+                                           "refund_fee");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if (1 == fee_cmp)
@@ -402,8 +408,10 @@ refund_transaction (void *cls,
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
   {
     TALER_LOG_WARNING ("Failed to store /refund information in database\n");
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_REFUND_STORE_DB_ERROR);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_REFUND_STORE_DB_ERROR,
+                                           "could not persist store information");
     return qs;
   }
   /* Success or soft failure */
@@ -443,17 +451,19 @@ verify_and_execute_refund (struct MHD_Connection *connection,
                                  &refund->refund_fee) )
   {
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_REFUND_FEE_CURRENCY_MISSMATCH,
-                                           "refund_fee");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_REFUND_FEE_CURRENCY_MISSMATCH,
+                                       "refund_fee");
   }
   if (-1 == TALER_amount_cmp (&refund->refund_amount,
                               &refund->refund_fee) )
   {
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_arg_invalid (connection,
-                                           TALER_EC_REFUND_FEE_ABOVE_AMOUNT,
-                                           "refund_amount");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       TALER_EC_REFUND_FEE_ABOVE_AMOUNT,
+                                       "refund_amount");
   }
   if (GNUNET_OK !=
       GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MERCHANT_REFUND,
@@ -462,9 +472,10 @@ verify_and_execute_refund (struct MHD_Connection *connection,
                                   &refund->merchant_pub.eddsa_pub))
   {
     TALER_LOG_WARNING ("Invalid signature on /refund request\n");
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_REFUND_MERCHANT_SIGNATURE_INVALID,
-                                                 "merchant_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_REFUND_MERCHANT_SIGNATURE_INVALID,
+                                       "merchant_sig");
   }
   if (GNUNET_OK !=
       TEH_DB_run_transaction (connection,
@@ -514,18 +525,18 @@ TEH_REFUND_handler_refund (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_SYSERR == res)
     return MHD_NO; /* hard failure */
diff --git a/src/exchange/taler-exchange-httpd_reserve_status.c b/src/exchange/taler-exchange-httpd_reserve_status.c
index 4f9761485..60cdd4f5a 100644
--- a/src/exchange/taler-exchange-httpd_reserve_status.c
+++ b/src/exchange/taler-exchange-httpd_reserve_status.c
@@ -23,8 +23,9 @@
 #include "platform.h"
 #include <gnunet/gnunet_util_lib.h>
 #include <jansson.h>
+#include "taler_mhd_lib.h"
+#include "taler_json_lib.h"
 #include "taler-exchange-httpd_reserve_status.h"
-#include "taler-exchange-httpd_parsing.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_keystate.h"
 
@@ -47,15 +48,16 @@ reply_reserve_status_success (struct MHD_Connection *connection,
   json_history = TEH_RESPONSE_compile_reserve_history (rh,
                                                        &balance);
   if (NULL == json_history)
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_RESERVE_STATUS_DB_ERROR,
-                                              "balance calculation failure");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_RESERVE_STATUS_DB_ERROR,
+                                       "balance calculation failure");
   json_balance = TALER_JSON_from_amount (&balance);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o, s:o}",
-                                       "balance", json_balance,
-                                       "history", json_history);
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o, s:o}",
+                                    "balance", json_balance,
+                                    "history", json_history);
 }
 
 
@@ -135,11 +137,11 @@ TEH_RESERVE_handler_reserve_status (struct TEH_RequestHandler *rh,
   int res;
   int mhd_ret;
 
-  res = TEH_PARSE_mhd_request_arg_data (connection,
-                                        "reserve_pub",
-                                        &rsc.reserve_pub,
-                                        sizeof (struct
-                                                TALER_ReservePublicKeyP));
+  res = TALER_MHD_parse_request_arg_data (connection,
+                                          "reserve_pub",
+                                          &rsc.reserve_pub,
+                                          sizeof (struct
+                                                  TALER_ReservePublicKeyP));
   if (GNUNET_SYSERR == res)
     return MHD_NO; /* internal error */
   if (GNUNET_NO == res)
@@ -155,14 +157,14 @@ TEH_RESERVE_handler_reserve_status (struct TEH_RequestHandler *rh,
 
   /* generate proper response */
   if (NULL == rsc.rh)
-    return TEH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_NOT_FOUND,
-                                         "{s:s, s:s, s:I}",
-                                         "error", "Reserve not found",
-                                         "parameter", "withdraw_pub",
-                                         "code",
-                                         (json_int_t)
-                                         TALER_EC_RESERVE_STATUS_UNKNOWN);
+    return TALER_MHD_reply_json_pack (connection,
+                                      MHD_HTTP_NOT_FOUND,
+                                      "{s:s, s:s, s:I}",
+                                      "error", "Reserve not found",
+                                      "parameter", "withdraw_pub",
+                                      "code",
+                                      (json_int_t)
+                                      TALER_EC_RESERVE_STATUS_UNKNOWN);
   mhd_ret = reply_reserve_status_success (connection,
                                           rsc.rh);
   TEH_plugin->free_reserve_history (TEH_plugin->cls,
diff --git a/src/exchange/taler-exchange-httpd_reserve_withdraw.c b/src/exchange/taler-exchange-httpd_reserve_withdraw.c
index 578aace31..8b59817a7 100644
--- a/src/exchange/taler-exchange-httpd_reserve_withdraw.c
+++ b/src/exchange/taler-exchange-httpd_reserve_withdraw.c
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014-2017 GNUnet e.V.
+  Copyright (C) 2014-2019 Taler Systems SA
 
   TALER is free software; you can redistribute it and/or modify
   it under the terms of the GNU Affero General Public License as
@@ -16,7 +16,6 @@
   Public License along with TALER; see the file COPYING.  If not,
   see <http://www.gnu.org/licenses/>
 */
-
 /**
  * @file taler-exchange-httpd_reserve_withdraw.c
  * @brief Handle /reserve/withdraw requests
@@ -27,8 +26,9 @@
 #include "platform.h"
 #include <gnunet/gnunet_util_lib.h>
 #include <jansson.h>
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_reserve_withdraw.h"
-#include "taler-exchange-httpd_parsing.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_keystate.h"
 
@@ -65,20 +65,21 @@ reply_reserve_withdraw_insufficient_funds (struct MHD_Connection *connection,
       /* Address the case where the ptr is not null, but
        * it fails "internally" to dump as string (= corrupted).  */
       || (0 == json_dumpb (json_history, NULL, 0, 0)))
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_WITHDRAW_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS,
-                                              "balance calculation failure");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_WITHDRAW_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS,
+                                       "balance calculation failure");
   json_balance = TALER_JSON_from_amount (&balance);
 
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_FORBIDDEN,
-                                       "{s:s, s:I, s:o, s:o}",
-                                       "error", "Insufficient funds",
-                                       "code",
-                                       (json_int_t)
-                                       TALER_EC_WITHDRAW_INSUFFICIENT_FUNDS,
-                                       "balance", json_balance,
-                                       "history", json_history);
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_CONFLICT,
+                                    "{s:s, s:I, s:o, s:o}",
+                                    "error", "Insufficient funds",
+                                    "code",
+                                    (json_int_t)
+                                    TALER_EC_WITHDRAW_INSUFFICIENT_FUNDS,
+                                    "balance", json_balance,
+                                    "history", json_history);
 }
 
 
@@ -98,10 +99,10 @@ reply_reserve_withdraw_success (struct MHD_Connection *connection,
   json_t *sig_json;
 
   sig_json = GNUNET_JSON_from_rsa_signature (collectable->sig.rsa_signature);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "ev_sig", sig_json);
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "ev_sig", sig_json);
 }
 
 
@@ -209,8 +210,10 @@ withdraw_transaction (void *cls,
   {
     GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_WITHDRAW_DB_FETCH_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_WITHDRAW_DB_FETCH_ERROR,
+                                             "failed to fetch withdraw data");
     wc->collectable.sig = denom_sig;
     return qs;
   }
@@ -252,15 +255,18 @@ withdraw_transaction (void *cls,
   if (0 > qs)
   {
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_WITHDRAW_DB_FETCH_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_WITHDRAW_DB_FETCH_ERROR,
+                                             "failed to fetch reserve data");
     return qs;
   }
   if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
   {
-    *mhd_ret = TEH_RESPONSE_reply_arg_unknown (connection,
-                                               TALER_EC_WITHDRAW_RESERVE_UNKNOWN,
-                                               "reserve_pub");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_WITHDRAW_RESERVE_UNKNOWN,
+                                           "reserve_pub");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if (0 < TALER_amount_cmp (&wc->amount_required,
@@ -286,8 +292,10 @@ withdraw_transaction (void *cls,
     if (NULL == rh)
     {
       if (GNUNET_DB_STATUS_HARD_ERROR == qs)
-        *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                         TALER_EC_WITHDRAW_DB_FETCH_ERROR);
+        *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                               MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                               TALER_EC_WITHDRAW_DB_FETCH_ERROR,
+                                               "failed to fetch reserve history");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
     *mhd_ret = reply_reserve_withdraw_insufficient_funds (connection,
@@ -308,9 +316,10 @@ withdraw_transaction (void *cls,
     if (NULL == wc->collectable.sig.rsa_signature)
     {
       GNUNET_break (0);
-      *mhd_ret = TEH_RESPONSE_reply_internal_error (connection,
-                                                    TALER_EC_WITHDRAW_SIGNATURE_FAILED,
-                                                    "Internal error");
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_WITHDRAW_SIGNATURE_FAILED,
+                                             "Failed to create signature");
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
   }
@@ -330,8 +339,10 @@ withdraw_transaction (void *cls,
   {
     GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_WITHDRAW_DB_STORE_ERROR);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_WITHDRAW_DB_STORE_ERROR,
+                                             "failed to persist withdraw data");
     return qs;
   }
   return qs;
@@ -383,18 +394,18 @@ TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &root);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &root);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == root) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             root,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   root,
+                                   spec);
   json_decref (root);
   if (GNUNET_OK != res)
     return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
@@ -403,9 +414,10 @@ TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
   {
     TALER_LOG_ERROR ("Lacking keys to operate\n");
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
   wc.dki = TEH_KS_denomination_key_lookup_by_hash (wc.key_state,
                                                    &wc.denom_pub_hash,
@@ -416,9 +428,10 @@ TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
   {
     GNUNET_JSON_parse_free (spec);
     TEH_KS_release (wc.key_state);
-    return TEH_RESPONSE_reply_with_error (connection,
-                                          ec,
-                                          hc);
+    return TALER_MHD_reply_with_error (connection,
+                                       hc,
+                                       ec,
+                                       "could not find denomination key");
   }
   GNUNET_assert (NULL != wc.dki->denom_priv.rsa_private_key);
   TALER_amount_ntoh (&amount,
@@ -432,9 +445,10 @@ TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
   {
     GNUNET_JSON_parse_free (spec);
     TEH_KS_release (wc.key_state);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_WITHDRAW_AMOUNT_FEE_OVERFLOW,
-                                              "amount overflow for value plus withdraw fee");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_WITHDRAW_AMOUNT_FEE_OVERFLOW,
+                                       "amount overflow for value plus withdraw fee");
   }
   TALER_amount_hton (&wc.wsrd.amount_with_fee,
                      &wc.amount_required);
@@ -460,9 +474,10 @@ TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
       "Client supplied invalid signature for /reserve/withdraw request\n");
     GNUNET_JSON_parse_free (spec);
     TEH_KS_release (wc.key_state);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_WITHDRAW_RESERVE_SIGNATURE_INVALID,
-                                                 "reserve_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_WITHDRAW_RESERVE_SIGNATURE_INVALID,
+                                       "reserve_sig");
   }
 
 #if OPTIMISTIC_SIGN
@@ -476,9 +491,10 @@ TEH_RESERVE_handler_reserve_withdraw (struct TEH_RequestHandler *rh,
     GNUNET_break (0);
     GNUNET_JSON_parse_free (spec);
     TEH_KS_release (wc.key_state);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_WITHDRAW_SIGNATURE_FAILED,
-                                              "Internal error");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_WITHDRAW_SIGNATURE_FAILED,
+                                       "Failed to sign");
   }
 #endif
 
diff --git a/src/exchange/taler-exchange-httpd_responses.c b/src/exchange/taler-exchange-httpd_responses.c
index 048a8bef0..4ef0f2d15 100644
--- a/src/exchange/taler-exchange-httpd_responses.c
+++ b/src/exchange/taler-exchange-httpd_responses.c
@@ -27,6 +27,7 @@
 #include "taler-exchange-httpd_responses.h"
 #include "taler_util.h"
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler-exchange-httpd_keystate.h"
 
 /**
@@ -39,453 +40,6 @@
 
 
 /**
- * Add headers we want to return in every response.
- * Useful for testing, like if we want to always close
- * connections.
- *
- * @param response response to modify
- */
-void
-TEH_RESPONSE_add_global_headers (struct MHD_Response *response)
-{
-  if (TEH_exchange_connection_close)
-    GNUNET_break (MHD_YES ==
-                  MHD_add_response_header (response,
-                                           MHD_HTTP_HEADER_CONNECTION,
-                                           "close"));
-}
-
-
-/**
- * Is HTTP body deflate compression supported by the client?
- *
- * @param connection connection to check
- * @return #MHD_YES if 'deflate' compression is allowed
- *
- * Note that right now we're ignoring q-values, which is technically
- * not correct, and also do not support "*" anywhere but in a line by
- * itself.  This should eventually be fixed, see also
- * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
- */
-int
-TEH_RESPONSE_can_compress (struct MHD_Connection *connection)
-{
-  const char *ae;
-  const char *de;
-
-  ae = MHD_lookup_connection_value (connection,
-                                    MHD_HEADER_KIND,
-                                    MHD_HTTP_HEADER_ACCEPT_ENCODING);
-  if (NULL == ae)
-    return MHD_NO;
-  if (0 == strcmp (ae,
-                   "*"))
-    return MHD_YES;
-  de = strstr (ae,
-               "deflate");
-  if (NULL == de)
-    return MHD_NO;
-  if ( ( (de == ae) ||
-         (de[-1] == ',') ||
-         (de[-1] == ' ') ) &&
-       ( (de[strlen ("deflate")] == '\0') ||
-         (de[strlen ("deflate")] == ',') ||
-         (de[strlen ("deflate")] == ';') ) )
-    return MHD_YES;
-  return MHD_NO;
-}
-
-
-/**
- * Try to compress a response body.  Updates @a buf and @a buf_size.
- *
- * @param[in,out] buf pointer to body to compress
- * @param[in,out] buf_size pointer to initial size of @a buf
- * @return #MHD_YES if @a buf was compressed
- */
-int
-TEH_RESPONSE_body_compress (void **buf,
-                            size_t *buf_size)
-{
-  Bytef *cbuf;
-  uLongf cbuf_size;
-  int ret;
-
-  cbuf_size = compressBound (*buf_size);
-  cbuf = malloc (cbuf_size);
-  if (NULL == cbuf)
-    return MHD_NO;
-  ret = compress (cbuf,
-                  &cbuf_size,
-                  (const Bytef *) *buf,
-                  *buf_size);
-  if ( (Z_OK != ret) ||
-       (cbuf_size >= *buf_size) )
-  {
-    /* compression failed */
-    free (cbuf);
-    return MHD_NO;
-  }
-  free (*buf);
-  *buf = (void *) cbuf;
-  *buf_size = (size_t) cbuf_size;
-  return MHD_YES;
-}
-
-
-/**
- * Send JSON object as response.
- *
- * @param connection the MHD connection
- * @param json the json object
- * @param response_code the http response code
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_json (struct MHD_Connection *connection,
-                         const json_t *json,
-                         unsigned int response_code)
-{
-  struct MHD_Response *resp;
-  void *json_str;
-  size_t json_len;
-  int ret;
-  int comp;
-
-  json_str = json_dumps (json,
-                         JSON_INDENT (2));
-  if (NULL == json_str)
-  {
-    /**
-     * This log helps to figure out which
-     * function called this one and assert-failed.
-     */
-    TALER_LOG_ERROR ("Aborting json-packing for HTTP code: %u\n",
-                     response_code);
-
-    GNUNET_assert (0);
-    return MHD_NO;
-  }
-  json_len = strlen (json_str);
-  /* try to compress the body */
-  comp = MHD_NO;
-  if (MHD_YES ==
-      TEH_RESPONSE_can_compress (connection))
-    comp = TEH_RESPONSE_body_compress (&json_str,
-                                       &json_len);
-  resp = MHD_create_response_from_buffer (json_len,
-                                          json_str,
-                                          MHD_RESPMEM_MUST_FREE);
-  if (NULL == resp)
-  {
-    free (json_str);
-    GNUNET_break (0);
-    return MHD_NO;
-  }
-  TEH_RESPONSE_add_global_headers (resp);
-  GNUNET_break (MHD_YES ==
-                MHD_add_response_header (resp,
-                                         MHD_HTTP_HEADER_CONTENT_TYPE,
-                                         "application/json"));
-  if (MHD_YES == comp)
-  {
-    /* Need to indicate to client that body is compressed */
-    if (MHD_NO ==
-        MHD_add_response_header (resp,
-                                 MHD_HTTP_HEADER_CONTENT_ENCODING,
-                                 "deflate"))
-    {
-      GNUNET_break (0);
-      MHD_destroy_response (resp);
-      return MHD_NO;
-    }
-  }
-  ret = MHD_queue_response (connection,
-                            response_code,
-                            resp);
-  MHD_destroy_response (resp);
-  return ret;
-}
-
-
-/**
- * Function to call to handle the request by building a JSON
- * reply from a format string and varargs.
- *
- * @param connection the MHD connection to handle
- * @param response_code HTTP response code to use
- * @param fmt format string for pack
- * @param ... varargs
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_json_pack (struct MHD_Connection *connection,
-                              unsigned int response_code,
-                              const char *fmt,
-                              ...)
-{
-  json_t *json;
-  va_list argp;
-  int ret;
-  json_error_t jerror;
-
-  va_start (argp, fmt);
-  json = json_vpack_ex (&jerror, 0, fmt, argp);
-  va_end (argp);
-  if (NULL == json)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Failed to pack JSON with format `%s': %s\n",
-                fmt,
-                jerror.text);
-    GNUNET_break (0);
-    return MHD_NO;
-  }
-  ret = TEH_RESPONSE_reply_json (connection,
-                                 json,
-                                 response_code);
-  json_decref (json);
-  return ret;
-}
-
-
-/**
- * Send a response indicating an invalid argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_arg_invalid (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "invalid parameter",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating an argument refering to a
- * resource unknown to the exchange (i.e. unknown reserve or
- * denomination key).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_arg_unknown (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_NOT_FOUND,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "unknown entity referenced",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating an invalid signature.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_signature_invalid (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec,
-                                      const char *param_name)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_UNAUTHORIZED,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "invalid signature",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating a missing argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is missing
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_arg_missing (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "missing parameter",
-                                       "code", (json_int_t) ec,
-                                       "parameter", param_name);
-}
-
-
-/**
- * Send a response indicating an internal error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the internal error's nature
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_internal_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "internal error",
-                                       "code", (json_int_t) ec,
-                                       "hint", hint);
-}
-
-
-/**
- * Send a response indicating an error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param http_status HTTP status code to use
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_with_error (struct MHD_Connection *connection,
-                               enum TALER_ErrorCode ec,
-                               unsigned int http_status)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       http_status,
-                                       "{s:I}",
-                                       "code", (json_int_t) ec);
-}
-
-
-/**
- * Send a response indicating an external error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the error's nature
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_external_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I, s:s}",
-                                       "error", "client error",
-                                       "code", (json_int_t) ec,
-                                       "hint", hint);
-}
-
-
-/**
- * Send a response indicating an error committing a
- * transaction (concurrent interference).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_commit_error (struct MHD_Connection *connection,
-                                 enum TALER_ErrorCode ec)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
-                                       "{s:s, s:I}",
-                                       "error", "commit failure",
-                                       "code", (json_int_t) ec);
-}
-
-
-/**
- * Send a response indicating a failure to talk to the Exchange's
- * database.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_internal_db_error (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec)
-{
-  return TEH_RESPONSE_reply_internal_error (connection,
-                                            ec,
-                                            "Failure in database interaction");
-}
-
-
-/**
- * Send a response indicating that the request was too big.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_request_too_large (struct MHD_Connection *connection)
-{
-  struct MHD_Response *resp;
-  int ret;
-
-  resp = MHD_create_response_from_buffer (0,
-                                          NULL,
-                                          MHD_RESPMEM_PERSISTENT);
-  if (NULL == resp)
-    return MHD_NO;
-  TEH_RESPONSE_add_global_headers (resp);
-  ret = MHD_queue_response (connection,
-                            MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
-                            resp);
-  MHD_destroy_response (resp);
-  return ret;
-}
-
-
-/**
- * Send a response indicating that the JSON was malformed.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_invalid_json (struct MHD_Connection *connection)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_BAD_REQUEST,
-                                       "{s:s, s:I}",
-                                       "error", "invalid json",
-                                       "code",
-                                       (json_int_t) TALER_EC_JSON_INVALID);
-}
-
-
-/**
  * Compile the transaction history of a coin into a JSON object.
  *
  * @param tl transaction history to JSON-ify
@@ -874,15 +428,16 @@ TEH_RESPONSE_reply_coin_insufficient_funds (struct MHD_Connection *connection,
 
   history = TEH_RESPONSE_compile_transaction_history (tl);
   if (NULL == history)
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_COIN_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS,
-                                              "failed to convert transaction history to JSON");
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_FORBIDDEN,
-                                       "{s:s, s:I, s:o}",
-                                       "error", "insufficient funds",
-                                       "code", (json_int_t) ec,
-                                       "history", history);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_COIN_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS,
+                                       "failed to convert transaction history to JSON");
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_CONFLICT,
+                                    "{s:s, s:I, s:o}",
+                                    "error", "insufficient funds",
+                                    "code", (json_int_t) ec,
+                                    "history", history);
 }
 
 
@@ -1170,25 +725,4 @@ TEH_RESPONSE_compile_reserve_history (const struct
 }
 
 
-/**
- * A merchant asked for details about a deposit, but
- * we do not know anything about the deposit. Generate the
- * 404 reply.
- *
- * @param connection connection to the client
- * @param ec Taler error code
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_transaction_unknown (struct MHD_Connection *connection,
-                                        enum TALER_ErrorCode ec)
-{
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_NOT_FOUND,
-                                       "{s:s, s:I}",
-                                       "error", "Deposit unknown",
-                                       "code", (json_int_t) ec);
-}
-
-
 /* end of taler-exchange-httpd_responses.c */
diff --git a/src/exchange/taler-exchange-httpd_responses.h b/src/exchange/taler-exchange-httpd_responses.h
index 9b6a78859..ec0515829 100644
--- a/src/exchange/taler-exchange-httpd_responses.h
+++ b/src/exchange/taler-exchange-httpd_responses.h
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014 GNUnet e.V.
+  Copyright (C) 2014-2019 GNUnet e.V.
 
   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU Affero General Public License as published by the Free Software
@@ -13,7 +13,6 @@
   You should have received a copy of the GNU Affero General Public License along with
   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */
-
 /**
  * @file taler-exchange-httpd_responses.h
  * @brief API for generating generic replies of the exchange; these
@@ -35,216 +34,6 @@
 
 
 /**
- * Add headers we want to return in every response.
- * Useful for testing, like if we want to always close
- * connections.
- *
- * @param response response to modify
- */
-void
-TEH_RESPONSE_add_global_headers (struct MHD_Response *response);
-
-
-/**
- * Try to compress a response body.  Updates @a buf and @a buf_size.
- *
- * @param[in,out] buf pointer to body to compress
- * @param[in,out] buf_size pointer to initial size of @a buf
- * @return #MHD_YES if @a buf was compressed
- */
-int
-TEH_RESPONSE_body_compress (void **buf,
-                            size_t *buf_size);
-
-
-/**
- * Is HTTP body deflate compression supported by the client?
- *
- * @param connection connection to check
- * @return #MHD_YES if 'deflate' compression is allowed
- */
-int
-TEH_RESPONSE_can_compress (struct MHD_Connection *connection);
-
-
-/**
- * Send JSON object as response.
- *
- * @param connection the MHD connection
- * @param json the json object
- * @param response_code the http response code
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_json (struct MHD_Connection *connection,
-                         const json_t *json,
-                         unsigned int response_code);
-
-
-/**
- * Function to call to handle the request by building a JSON
- * reply from a format string and varargs.
- *
- * @param connection the MHD connection to handle
- * @param response_code HTTP response code to use
- * @param fmt format string for pack
- * @param ... varargs
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_json_pack (struct MHD_Connection *connection,
-                              unsigned int response_code,
-                              const char *fmt,
-                              ...);
-
-
-/**
- * Send a response indicating an invalid signature.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_signature_invalid (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec,
-                                      const char *param_name);
-
-
-/**
- * Send a response indicating an invalid argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_arg_invalid (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name);
-
-
-/**
- * Send a response indicating an argument refering to a
- * resource unknown to the exchange (i.e. unknown reserve or
- * denomination key).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is invalid
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_arg_unknown (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name);
-
-
-/**
- * Send a response indicating a missing argument.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param param_name the parameter that is missing
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_arg_missing (struct MHD_Connection *connection,
-                                enum TALER_ErrorCode ec,
-                                const char *param_name);
-
-
-/**
- * Send a response indicating an internal error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the internal error's nature
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_internal_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint);
-
-
-/**
- * Send a response indicating an error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param http_status HTTP status code to use
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_with_error (struct MHD_Connection *connection,
-                               enum TALER_ErrorCode ec,
-                               unsigned int http_status);
-
-
-/**
- * Send a response indicating an external error.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @param hint hint about the error's nature
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_external_error (struct MHD_Connection *connection,
-                                   enum TALER_ErrorCode ec,
-                                   const char *hint);
-
-
-/**
- * Send a response indicating an error committing a
- * transaction (concurrent interference).
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_commit_error (struct MHD_Connection *connection,
-                                 enum TALER_ErrorCode ec);
-
-
-/**
- * Send a response indicating a failure to talk to the Exchange's
- * database.
- *
- * @param connection the MHD connection to use
- * @param ec error code uniquely identifying the error
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_internal_db_error (struct MHD_Connection *connection,
-                                      enum TALER_ErrorCode ec);
-
-
-/**
- * Send a response indicating that the request was too big.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_request_too_large (struct MHD_Connection *connection);
-
-
-/**
- * Send a response indicating that the JSON was malformed.
- *
- * @param connection the MHD connection to use
- * @return a MHD result code
- */
-int
-TEH_RESPONSE_reply_invalid_json (struct MHD_Connection *connectionx);
-
-
-/**
  * Compile the history of a reserve into a JSON object
  * and calculate the total balance.
  *
@@ -277,20 +66,6 @@ TEH_RESPONSE_reply_coin_insufficient_funds (struct MHD_Connection *connection,
 
 
 /**
- * A merchant asked for details about a deposit, but
- * we do not know anything about the deposit. Generate the
- * 404 reply.
- *
- * @param connection connection to the client
- * @param ec Taler error code
- * @return MHD result code
- */
-int
-TEH_RESPONSE_reply_transaction_unknown (struct MHD_Connection *connection,
-                                        enum TALER_ErrorCode ec);
-
-
-/**
  * Compile the transaction history of a coin into a JSON object.
  *
  * @param tl transaction history to JSON-ify
diff --git a/src/exchange/taler-exchange-httpd_test.c b/src/exchange/taler-exchange-httpd_test.c
index 0a64f267f..4b3c50b2c 100644
--- a/src/exchange/taler-exchange-httpd_test.c
+++ b/src/exchange/taler-exchange-httpd_test.c
@@ -24,9 +24,9 @@
 #include <gnunet/gnunet_json_lib.h>
 #include <jansson.h>
 #include <microhttpd.h>
+#include "taler_mhd_lib.h"
 #include "taler_signatures.h"
 #include "taler-exchange-httpd_test.h"
-#include "taler-exchange-httpd_parsing.h"
 #include "taler-exchange-httpd_responses.h"
 
 
@@ -69,18 +69,18 @@ TEH_TEST_handler_test_base32 (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
   GNUNET_CRYPTO_hash (in_ptr,
@@ -88,11 +88,11 @@ TEH_TEST_handler_test_base32 (struct TEH_RequestHandler *rh,
                       &hc);
   GNUNET_JSON_parse_free (spec);
   json_decref (json);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "output",
-                                       GNUNET_JSON_from_data_auto (&hc));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "output",
+                                    GNUNET_JSON_from_data_auto (&hc));
 }
 
 
@@ -134,18 +134,18 @@ TEH_TEST_handler_test_encrypt (struct TEH_RequestHandler *rh,
   };
   char *out;
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
@@ -172,11 +172,11 @@ TEH_TEST_handler_test_encrypt (struct TEH_RequestHandler *rh,
                                 in_ptr_size);
   GNUNET_free (out);
   GNUNET_JSON_parse_free (spec);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "output",
-                                       json);
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "output",
+                                    json);
 }
 
 
@@ -214,18 +214,18 @@ TEH_TEST_handler_test_hkdf (struct TEH_RequestHandler *rh,
     GNUNET_JSON_spec_end ()
   };
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
@@ -237,11 +237,11 @@ TEH_TEST_handler_test_hkdf (struct TEH_RequestHandler *rh,
                                     NULL, 0));
   GNUNET_JSON_parse_free (spec);
   json = GNUNET_JSON_from_data_auto (&hc);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "output",
-                                       json);
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "output",
+                                    json);
 }
 
 
@@ -277,18 +277,18 @@ TEH_TEST_handler_test_ecdhe (struct TEH_RequestHandler *rh,
     GNUNET_JSON_spec_end ()
   };
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
@@ -298,16 +298,17 @@ TEH_TEST_handler_test_ecdhe (struct TEH_RequestHandler *rh,
                               &hc))
   {
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_TEST_ECDH_ERROR,
-                                              "Failed to perform ECDH");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TEST_ECDH_ERROR,
+                                       "Failed to perform ECDH");
   }
   GNUNET_JSON_parse_free (spec);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "ecdh_hash",
-                                       GNUNET_JSON_from_data_auto (&hc));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "ecdh_hash",
+                                    GNUNET_JSON_from_data_auto (&hc));
 }
 
 
@@ -345,18 +346,18 @@ TEH_TEST_handler_test_eddsa (struct TEH_RequestHandler *rh,
   };
   struct GNUNET_CRYPTO_EddsaPrivateKey *pk;
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
@@ -369,9 +370,10 @@ TEH_TEST_handler_test_eddsa (struct TEH_RequestHandler *rh,
                                   &pub))
   {
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_TEST_EDDSA_INVALID,
-                                                 "eddsa_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_TEST_EDDSA_INVALID,
+                                       "eddsa_sig");
   }
   GNUNET_JSON_parse_free (spec);
   pk = GNUNET_CRYPTO_eddsa_key_create ();
@@ -382,20 +384,21 @@ TEH_TEST_handler_test_eddsa (struct TEH_RequestHandler *rh,
                                 &sig))
   {
     GNUNET_free (pk);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_TEST_EDDSA_ERROR,
-                                              "Failed to EdDSA-sign");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TEST_EDDSA_ERROR,
+                                       "Failed to EdDSA-sign");
   }
   GNUNET_CRYPTO_eddsa_key_get_public (pk,
                                       &pub);
   GNUNET_free (pk);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o, s:o}",
-                                       "eddsa_pub",
-                                       GNUNET_JSON_from_data_auto (&pub),
-                                       "eddsa_sig",
-                                       GNUNET_JSON_from_data_auto (&sig));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o, s:o}",
+                                    "eddsa_pub",
+                                    GNUNET_JSON_from_data_auto (&pub),
+                                    "eddsa_sig",
+                                    GNUNET_JSON_from_data_auto (&sig));
 }
 
 
@@ -425,23 +428,25 @@ TEH_TEST_handler_test_rsa_get (struct TEH_RequestHandler *rh,
   if (NULL == rsa_pk)
   {
     GNUNET_break (0);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_TEST_RSA_GEN_ERROR,
-                                              "Failed to create RSA key");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TEST_RSA_GEN_ERROR,
+                                       "Failed to create RSA key");
   }
   pub = GNUNET_CRYPTO_rsa_private_key_get_public (rsa_pk);
   if (NULL == pub)
   {
     GNUNET_break (0);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_TEST_RSA_PUB_ERROR,
-                                              "Failed to get public RSA key");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TEST_RSA_PUB_ERROR,
+                                       "Failed to get public RSA key");
   }
-  res = TEH_RESPONSE_reply_json_pack (connection,
-                                      MHD_HTTP_OK,
-                                      "{s:o}",
-                                      "rsa_pub",
-                                      GNUNET_JSON_from_rsa_public_key (pub));
+  res = TALER_MHD_reply_json_pack (connection,
+                                   MHD_HTTP_OK,
+                                   "{s:o}",
+                                   "rsa_pub",
+                                   GNUNET_JSON_from_rsa_public_key (pub));
   GNUNET_CRYPTO_rsa_public_key_free (pub);
   return res;
 }
@@ -476,18 +481,18 @@ TEH_TEST_handler_test_rsa_sign (struct TEH_RequestHandler *rh,
     GNUNET_JSON_spec_end ()
   };
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
@@ -497,9 +502,10 @@ TEH_TEST_handler_test_rsa_sign (struct TEH_RequestHandler *rh,
   {
     GNUNET_break (0);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_TEST_RSA_GEN_ERROR,
-                                              "Failed to create RSA key");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TEST_RSA_GEN_ERROR,
+                                       "Failed to create RSA key");
   }
   sig = GNUNET_CRYPTO_rsa_sign_blinded (rsa_pk,
                                         in_ptr,
@@ -508,16 +514,17 @@ TEH_TEST_handler_test_rsa_sign (struct TEH_RequestHandler *rh,
   {
     GNUNET_break (0);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_TEST_RSA_SIGN_ERROR,
-                                              "Failed to RSA-sign");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TEST_RSA_SIGN_ERROR,
+                                       "Failed to RSA-sign");
   }
   GNUNET_JSON_parse_free (spec);
-  res = TEH_RESPONSE_reply_json_pack (connection,
-                                      MHD_HTTP_OK,
-                                      "{s:o}",
-                                      "rsa_blind_sig",
-                                      GNUNET_JSON_from_rsa_signature (sig));
+  res = TALER_MHD_reply_json_pack (connection,
+                                   MHD_HTTP_OK,
+                                   "{s:o}",
+                                   "rsa_blind_sig",
+                                   GNUNET_JSON_from_rsa_signature (sig));
   GNUNET_CRYPTO_rsa_signature_free (sig);
   return res;
 }
@@ -555,29 +562,29 @@ TEH_TEST_handler_test_transfer (struct TEH_RequestHandler *rh,
   };
   struct TALER_TransferSecretP secret;
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   json_decref (json);
   if (GNUNET_YES != res)
     return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
   TALER_link_reveal_transfer_secret (&trans_priv,
                                      &coin_pub,
                                      &secret);
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o}",
-                                       "secret",
-                                       GNUNET_JSON_from_data_auto (&secret));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o}",
+                                    "secret",
+                                    GNUNET_JSON_from_data_auto (&secret));
 }
 
 
@@ -601,11 +608,11 @@ TEH_TEST_handler_test (struct TEH_RequestHandler *rh,
   json_t *json;
   int res;
 
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
diff --git a/src/exchange/taler-exchange-httpd_track_transaction.c b/src/exchange/taler-exchange-httpd_track_transaction.c
index 3b8d14a01..757f28bad 100644
--- a/src/exchange/taler-exchange-httpd_track_transaction.c
+++ b/src/exchange/taler-exchange-httpd_track_transaction.c
@@ -23,8 +23,9 @@
 #include <jansson.h>
 #include <microhttpd.h>
 #include <pthread.h>
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler_signatures.h"
-#include "taler-exchange-httpd_parsing.h"
 #include "taler-exchange-httpd_keystate.h"
 #include "taler-exchange-httpd_track_transaction.h"
 #include "taler-exchange-httpd_responses.h"
@@ -42,12 +43,12 @@ static int
 reply_transfer_pending (struct MHD_Connection *connection,
                         struct GNUNET_TIME_Absolute planned_exec_time)
 {
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_ACCEPTED,
-                                       "{s:o}",
-                                       "execution_time",
-                                       GNUNET_JSON_from_time_abs (
-                                         planned_exec_time));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_ACCEPTED,
+                                    "{s:o}",
+                                    "execution_time",
+                                    GNUNET_JSON_from_time_abs (
+                                      planned_exec_time));
 }
 
 
@@ -92,24 +93,25 @@ reply_track_transaction (struct MHD_Connection *connection,
                    &pub,
                    &sig))
   {
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o, s:o, s:o, s:o, s:o}",
-                                       "wtid", GNUNET_JSON_from_data_auto (
-                                         wtid),
-                                       "execution_time",
-                                       GNUNET_JSON_from_time_abs (exec_time),
-                                       "coin_contribution",
-                                       TALER_JSON_from_amount (
-                                         coin_contribution),
-                                       "exchange_sig",
-                                       GNUNET_JSON_from_data_auto (&sig),
-                                       "exchange_pub",
-                                       GNUNET_JSON_from_data_auto (&pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o, s:o, s:o, s:o, s:o}",
+                                    "wtid", GNUNET_JSON_from_data_auto (
+                                      wtid),
+                                    "execution_time",
+                                    GNUNET_JSON_from_time_abs (exec_time),
+                                    "coin_contribution",
+                                    TALER_JSON_from_amount (
+                                      coin_contribution),
+                                    "exchange_sig",
+                                    GNUNET_JSON_from_data_auto (&sig),
+                                    "exchange_pub",
+                                    GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -249,15 +251,19 @@ track_transaction_transaction (void *cls,
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
       GNUNET_break (0);
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_TRACK_TRANSACTION_DB_FETCH_FAILED);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_TRACK_TRANSACTION_DB_FETCH_FAILED,
+                                             "failed to fetch transaction data");
     }
     return qs;
   }
   if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
   {
-    *mhd_ret = TEH_RESPONSE_reply_transaction_unknown (connection,
-                                                       TALER_EC_TRACK_TRANSACTION_NOT_FOUND);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_TRACK_TRANSACTION_NOT_FOUND,
+                                           "transaction unknown");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   return qs;
@@ -295,9 +301,10 @@ check_and_handle_track_transaction_request (struct MHD_Connection *connection,
                                   &merchant_pub->eddsa_pub))
   {
     GNUNET_break_op (0);
-    return TEH_RESPONSE_reply_signature_invalid (connection,
-                                                 TALER_EC_TRACK_TRANSACTION_MERCHANT_SIGNATURE_INVALID,
-                                                 "merchant_sig");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       TALER_EC_TRACK_TRANSACTION_MERCHANT_SIGNATURE_INVALID,
+                                       "merchant_sig");
   }
   ctx.pending = GNUNET_NO;
   ctx.tps = tps;
@@ -314,8 +321,10 @@ check_and_handle_track_transaction_request (struct MHD_Connection *connection,
     return reply_transfer_pending (connection,
                                    ctx.execution_time);
   if (GNUNET_SYSERR == ctx.pending)
-    return TEH_RESPONSE_reply_internal_db_error (connection,
-                                                 TALER_EC_TRACK_TRANSACTION_DB_FEE_INCONSISTENT);
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_TRACK_TRANSACTION_DB_FEE_INCONSISTENT,
+                                       "fees are inconsistent");
   return reply_track_transaction (connection,
                                   &tps->h_contract_terms,
                                   &tps->h_wire,
@@ -357,18 +366,18 @@ TEH_TRACKING_handler_track_transaction (struct TEH_RequestHandler *rh,
   };
 
   (void) rh;
-  res = TEH_PARSE_post_json (connection,
-                             connection_cls,
-                             upload_data,
-                             upload_data_size,
-                             &json);
+  res = TALER_MHD_parse_post_json (connection,
+                                   connection_cls,
+                                   upload_data,
+                                   upload_data_size,
+                                   &json);
   if (GNUNET_SYSERR == res)
     return MHD_NO;
   if ( (GNUNET_NO == res) || (NULL == json) )
     return MHD_YES;
-  res = TEH_PARSE_json_data (connection,
-                             json,
-                             spec);
+  res = TALER_MHD_parse_json_data (connection,
+                                   json,
+                                   spec);
   if (GNUNET_OK != res)
   {
     json_decref (json);
diff --git a/src/exchange/taler-exchange-httpd_track_transfer.c b/src/exchange/taler-exchange-httpd_track_transfer.c
index cacbfaa85..f40d7c819 100644
--- a/src/exchange/taler-exchange-httpd_track_transfer.c
+++ b/src/exchange/taler-exchange-httpd_track_transfer.c
@@ -24,10 +24,11 @@
 #include <microhttpd.h>
 #include <pthread.h>
 #include "taler_signatures.h"
-#include "taler-exchange-httpd_parsing.h"
 #include "taler-exchange-httpd_keystate.h"
 #include "taler-exchange-httpd_track_transfer.h"
 #include "taler-exchange-httpd_responses.h"
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include "taler_wire_lib.h"
 
 
@@ -148,29 +149,30 @@ reply_track_transfer_details (struct MHD_Connection *connection,
                    &sig))
   {
     json_decref (deposits);
-    return TEH_RESPONSE_reply_internal_error (connection,
-                                              TALER_EC_EXCHANGE_BAD_CONFIGURATION,
-                                              "no keys");
+    return TALER_MHD_reply_with_error (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       TALER_EC_EXCHANGE_BAD_CONFIGURATION,
+                                       "no keys");
   }
 
-  return TEH_RESPONSE_reply_json_pack (connection,
-                                       MHD_HTTP_OK,
-                                       "{s:o, s:o, s:o, s:o, s:o, s:o, s:o, s:o}",
-                                       "total", TALER_JSON_from_amount (total),
-                                       "wire_fee", TALER_JSON_from_amount (
-                                         wire_fee),
-                                       "merchant_pub",
-                                       GNUNET_JSON_from_data_auto (
-                                         merchant_pub),
-                                       "H_wire", GNUNET_JSON_from_data_auto (
-                                         h_wire),
-                                       "execution_time",
-                                       GNUNET_JSON_from_time_abs (exec_time),
-                                       "deposits", deposits,
-                                       "exchange_sig",
-                                       GNUNET_JSON_from_data_auto (&sig),
-                                       "exchange_pub",
-                                       GNUNET_JSON_from_data_auto (&pub));
+  return TALER_MHD_reply_json_pack (connection,
+                                    MHD_HTTP_OK,
+                                    "{s:o, s:o, s:o, s:o, s:o, s:o, s:o, s:o}",
+                                    "total", TALER_JSON_from_amount (total),
+                                    "wire_fee", TALER_JSON_from_amount (
+                                      wire_fee),
+                                    "merchant_pub",
+                                    GNUNET_JSON_from_data_auto (
+                                      merchant_pub),
+                                    "H_wire", GNUNET_JSON_from_data_auto (
+                                      h_wire),
+                                    "execution_time",
+                                    GNUNET_JSON_from_time_abs (exec_time),
+                                    "deposits", deposits,
+                                    "exchange_sig",
+                                    GNUNET_JSON_from_data_auto (&sig),
+                                    "exchange_pub",
+                                    GNUNET_JSON_from_data_auto (&pub));
 }
 
 
@@ -396,23 +398,28 @@ track_transfer_transaction (void *cls,
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
     {
       GNUNET_break (0);
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_TRACK_TRANSFER_DB_FETCH_FAILED);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_TRACK_TRANSFER_DB_FETCH_FAILED,
+                                             "failed to fetch transaction data");
     }
     return qs;
   }
   if (GNUNET_SYSERR == ctx->is_valid)
   {
     GNUNET_break (0);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_TRACK_TRANSFER_DB_INCONSISTENT);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_TRACK_TRANSFER_DB_INCONSISTENT,
+                                           "exchange database internally inconsistent");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   if (GNUNET_NO == ctx->is_valid)
   {
-    *mhd_ret = TEH_RESPONSE_reply_arg_unknown (connection,
-                                               TALER_EC_TRACK_TRANSFER_WTID_NOT_FOUND,
-                                               "wtid");
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_NOT_FOUND,
+                                           TALER_EC_TRACK_TRANSFER_WTID_NOT_FOUND,
+                                           "wtid");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   qs = TEH_plugin->get_wire_fee (TEH_plugin->cls,
@@ -430,8 +437,10 @@ track_transfer_transaction (void *cls,
          (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS) )
     {
       GNUNET_break (0);
-      *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                       TALER_EC_TRACK_TRANSFER_WIRE_FEE_NOT_FOUND);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_TRACK_TRANSFER_WIRE_FEE_NOT_FOUND,
+                                             "did not find wire fee");
     }
     return qs;
   }
@@ -441,8 +450,10 @@ track_transfer_transaction (void *cls,
                              &ctx->wire_fee))
   {
     GNUNET_break (0);
-    *mhd_ret = TEH_RESPONSE_reply_internal_db_error (connection,
-                                                     TALER_EC_TRACK_TRANSFER_WIRE_FEE_INCONSISTENT);
+    *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                           MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                           TALER_EC_TRACK_TRANSFER_WIRE_FEE_INCONSISTENT,
+                                           "could not subtract wire fee");
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
   return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
@@ -492,11 +503,11 @@ TEH_TRACKING_handler_track_transfer (struct TEH_RequestHandler *rh,
   int mhd_ret;
 
   memset (&ctx, 0, sizeof (ctx));
-  res = TEH_PARSE_mhd_request_arg_data (connection,
-                                        "wtid",
-                                        &ctx.wtid,
-                                        sizeof (struct
-                                                TALER_WireTransferIdentifierRawP));
+  res = TALER_MHD_parse_request_arg_data (connection,
+                                          "wtid",
+                                          &ctx.wtid,
+                                          sizeof (struct
+                                                  TALER_WireTransferIdentifierRawP));
   if (GNUNET_SYSERR == res)
     return MHD_NO; /* internal error */
   if (GNUNET_NO == res)
diff --git a/src/exchange/taler-exchange-httpd_wire.c b/src/exchange/taler-exchange-httpd_wire.c
index 91c928f94..4e4c34db5 100644
--- a/src/exchange/taler-exchange-httpd_wire.c
+++ b/src/exchange/taler-exchange-httpd_wire.c
@@ -25,6 +25,7 @@
 #include "taler-exchange-httpd_validation.h"
 #include "taler-exchange-httpd_wire.h"
 #include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
 #include <jansson.h>
 
 /**
@@ -140,9 +141,9 @@ TEH_WIRE_handler_wire (struct TEH_RequestHandler *rh,
   (void) upload_data;
   (void) upload_data_size;
   GNUNET_assert (NULL != wire_methods);
-  return TEH_RESPONSE_reply_json (connection,
-                                  wire_methods,
-                                  MHD_HTTP_OK);
+  return TALER_MHD_reply_json (connection,
+                               wire_methods,
+                               MHD_HTTP_OK);
 }
 
 
diff --git a/src/exchange/taler-exchange-wirewatch.c b/src/exchange/taler-exchange-wirewatch.c
index 3699c9d3b..21f62cd82 100644
--- a/src/exchange/taler-exchange-wirewatch.c
+++ b/src/exchange/taler-exchange-wirewatch.c
@@ -733,10 +733,10 @@ main (int argc,
                           options,
                           &run, NULL))
   {
-    GNUNET_free ((void*) argv);
+    GNUNET_free ((void *) argv);
     return 1;
   }
-  GNUNET_free ((void*) argv);
+  GNUNET_free ((void *) argv);
   return global_ret;
 }
 
diff --git a/src/include/Makefile.am b/src/include/Makefile.am
index 1e624caa4..645bdc9f9 100644
--- a/src/include/Makefile.am
+++ b/src/include/Makefile.am
@@ -27,6 +27,7 @@ talerinclude_HEADERS = \
   taler_json_lib.h \
   taler_testing_lib.h \
   taler_util.h \
+  taler_mhd_lib.h \
   taler_pq_lib.h \
   taler_signatures.h \
   taler_wire_lib.h \
diff --git a/src/include/gauger.h b/src/include/gauger.h
index 7d66051b7..36dc055bb 100644
--- a/src/include/gauger.h
+++ b/src/include/gauger.h
@@ -35,7 +35,7 @@
         __gauger_v[7] = "-c"; \
         __gauger_v[8] = (char *) category;  \
         __gauger_v[9] = (char *) NULL; \
-        execvp ("gauger", (char*const*) __gauger_v); \
+        execvp ("gauger", (char *const *) __gauger_v); \
         perror ("gauger"); \
         _exit (1); \
       }else{ \
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index 917f3fc93..9986c9d10 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -188,7 +188,7 @@ enum TALER_ErrorCode
    * requested withdraw operation at this time.  The response includes
    * the current "balance" of the reserve as well as the transaction
    * "history" that lead to this balance.  This response is provided
-   * with HTTP status code MHD_HTTP_FORBIDDEN.
+   * with HTTP status code MHD_HTTP_CONFLICT.
    */
   TALER_EC_WITHDRAW_INSUFFICIENT_FUNDS = 1100,
 
@@ -340,7 +340,7 @@ enum TALER_ErrorCode
    * for the /deposit operation (i.e. due to double spending).
    * The "history" in the respose provides the transaction history
    * of the coin proving this fact.  This response is provided
-   * with HTTP status code MHD_HTTP_FORBIDDEN.
+   * with HTTP status code MHD_HTTP_CONFLICT.
    */
   TALER_EC_DEPOSIT_INSUFFICIENT_FUNDS = 1200,
 
@@ -496,7 +496,7 @@ enum TALER_ErrorCode
    * for the /refresh/melt operation.  The "history" in this
    * response provdes the "residual_value" of the coin, which may
    * be less than its "original_value".  This response is provided
-   * with HTTP status code MHD_HTTP_FORBIDDEN.
+   * with HTTP status code MHD_HTTP_CONFLICT.
    */
   TALER_EC_REFRESH_MELT_INSUFFICIENT_FUNDS = 1300,
 
@@ -929,7 +929,7 @@ enum TALER_ErrorCode
   /**
    * The given coin signature is invalid for the request.
    * This response is provided with an
-   * HTTP status code of MHD_HTTP_UNAUTHORIZED.
+   * HTTP status code of MHD_HTTP_FORBIDDEN.
    */
   TALER_EC_PAYBACK_SIGNATURE_INVALID = 1851,
 
@@ -1442,6 +1442,7 @@ enum TALER_ErrorCode
    * The amount to be refunded is inconsistent: either is lower than
    * the previous amount being awarded, or it is too big to be paid back.
    * In this second case, the fault stays on the business dept. side.
+   * Returned with an HTTP status of #MHD_HTTP_CONFLICT.
    */
   TALER_EC_REFUND_INCONSISTENT_AMOUNT = 2602,
 
@@ -1851,7 +1852,7 @@ enum TALER_ErrorCode
   /**
    * The sync service failed to access its database.
    * This response is provided with HTTP status code
-   * MHD_HTTP_INTERNAL_ERROR.
+   * MHD_HTTP_INTERNAL_SERVER_ERROR.
    */
   TALER_EC_SYNC_DB_FETCH_ERROR = 6000,
 
@@ -1905,7 +1906,7 @@ enum TALER_ErrorCode
    * The signature provided in the "Sync-Signature" header
    * does not match the account, old or new Etags.
    * This response is provided with HTTP status code
-   * MHD_HTTP_UNAUTHORIZED.
+   * MHD_HTTP_FORBIDDEN.
    */
   TALER_EC_SYNC_INVALID_SIGNATURE = 6007,
 
@@ -1985,7 +1986,6 @@ enum TALER_ErrorCode
    */
   TALER_EC_SYNC_PAYMENT_CHECK_ORDER_DB_ERROR = 6017,
 
-
   /**
    * End of error code range.
    */
diff --git a/src/include/taler_json_lib.h b/src/include/taler_json_lib.h
index 382bb19ee..6adb76b24 100644
--- a/src/include/taler_json_lib.h
+++ b/src/include/taler_json_lib.h
@@ -126,6 +126,19 @@ enum TALER_ErrorCode
 TALER_JSON_get_error_code (const json_t *json);
 
 
+/**
+ * Extract the Taler error code from the given @a data object, which is expected to be in JSON.
+ * Note that #TALER_EC_INVALID is returned if no "code" is present or if @a data is not in JSON.
+ *
+ * @param data response to extract the error code from
+ * @param data_size number of bytes in @a data
+ * @return the "code" value from @a json
+ */
+enum TALER_ErrorCode
+TALER_JSON_get_error_code2 (const void *data,
+                            size_t data_size);
+
+
 /* **************** /wire account offline signing **************** */
 
 /**
diff --git a/src/include/taler_mhd_lib.h b/src/include/taler_mhd_lib.h
new file mode 100644
index 000000000..cdbc8d290
--- /dev/null
+++ b/src/include/taler_mhd_lib.h
@@ -0,0 +1,393 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014 GNUnet e.V.
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler_mhd_lib.h
+ * @brief API for generating MHD replies
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#ifndef TALER_MHD_LIB_H
+#define TALER_MHD_LIB_H
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <jansson.h>
+#include <microhttpd.h>
+#include "taler_error_codes.h"
+
+/**
+ * Global options for response generation.
+ */
+enum TALER_MHD_GlobalOptions
+{
+
+  /**
+   * Use defaults.
+   */
+  TALER_MHD_GO_NONE = 0,
+
+  /**
+   * Add "Connection: Close" header.
+   */
+  TALER_MHD_GO_FORCE_CONNECTION_CLOSE = 1,
+
+  /**
+   * Disable use of compression, even if the client
+   * supports it.
+   */
+  TALER_MHD_GO_DISABLE_COMPRESSION = 2
+
+};
+
+
+/**
+ * Set global options for response generation
+ * within libtalermhd.
+ *
+ * @param go global options to use
+ */
+void
+TALER_MHD_setup (enum TALER_MHD_GlobalOptions go);
+
+
+/**
+ * Add headers we want to return in every response.
+ * Useful for testing, like if we want to always close
+ * connections.
+ *
+ * @param response response to modify
+ */
+void
+TALER_MHD_add_global_headers (struct MHD_Response *response);
+
+
+/**
+ * Try to compress a response body.  Updates @a buf and @a buf_size.
+ *
+ * @param[in,out] buf pointer to body to compress
+ * @param[in,out] buf_size pointer to initial size of @a buf
+ * @return #MHD_YES if @a buf was compressed
+ */
+int
+TALER_MHD_body_compress (void **buf,
+                         size_t *buf_size);
+
+
+/**
+ * Is HTTP body deflate compression supported by the client?
+ *
+ * @param connection connection to check
+ * @return #MHD_YES if 'deflate' compression is allowed
+ */
+int
+TALER_MHD_can_compress (struct MHD_Connection *connection);
+
+
+/**
+ * Send JSON object as response.
+ *
+ * @param connection the MHD connection
+ * @param json the json object
+ * @param response_code the http response code
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json (struct MHD_Connection *connection,
+                      const json_t *json,
+                      unsigned int response_code);
+
+
+/**
+ * Function to call to handle the request by building a JSON
+ * reply from a format string and varargs.
+ *
+ * @param connection the MHD connection to handle
+ * @param response_code HTTP response code to use
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json_pack (struct MHD_Connection *connection,
+                           unsigned int response_code,
+                           const char *fmt,
+                           ...);
+
+
+/**
+ * Send a response indicating an error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param http_status HTTP status code to use
+ * @param hint human readable hint about the error
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_with_error (struct MHD_Connection *connection,
+                            unsigned int http_status,
+                            enum TALER_ErrorCode ec,
+                            const char *hint);
+
+
+/**
+ * Make JSON response object.
+ *
+ * @param json the json object
+ * @return MHD response object
+ */
+struct MHD_Response *
+TALER_MHD_make_json (const json_t *json);
+
+
+/**
+ * Make JSON response object.
+ *
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD response object
+ */
+struct MHD_Response *
+TALER_MHD_make_json_pack (const char *fmt,
+                          ...);
+
+
+/**
+ * Create a response indicating an internal error.
+ *
+ * @param ec error code to return
+ * @param hint hint about the internal error's nature
+ * @return a MHD response object
+ */
+struct MHD_Response *
+TALER_MHD_make_error (enum TALER_ErrorCode ec,
+                      const char *hint);
+
+
+/**
+ * Send a response indicating that the request was too big.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_request_too_large (struct MHD_Connection *connection);
+
+
+/**
+ * Function to call to handle the request by sending
+ * back a redirect to the AGPL source code.
+ *
+ * @param connection the MHD connection to handle
+ * @param url where to redirect for the sources
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_agpl (struct MHD_Connection *connection,
+                      const char *url);
+
+
+/**
+ * Function to call to handle the request by sending
+ * back static data.
+ *
+ * @param rh context of the handler
+ * @param connection the MHD connection to handle
+ * @param http_status status code to return
+ * @param mime_type content-type to use
+ * @param body response payload
+ * @param body_size number of bytes in @a body
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_static (struct MHD_Connection *connection,
+                        unsigned int http_status,
+                        const char *mime_type,
+                        const char *body,
+                        size_t body_size);
+
+
+/**
+ * Process a POST request containing a JSON object.  This
+ * function realizes an MHD POST processor that will
+ * (incrementally) process JSON data uploaded to the HTTP
+ * server.  It will store the required state in the
+ * "connection_cls", which must be cleaned up using
+ * #TALER_MHD_post_cleanup_callback().
+ *
+ * @param connection the MHD connection
+ * @param con_cls the closure (points to a `struct Buffer *`)
+ * @param upload_data the POST data
+ * @param upload_data_size number of bytes in @a upload_data
+ * @param json the JSON object for a completed request
+ * @return
+ *    #GNUNET_YES if json object was parsed or at least
+ *               may be parsed in the future (call again);
+ *               `*json` will be NULL if we need to be called again,
+ *                and non-NULL if we are done.
+ *    #GNUNET_NO is request incomplete or invalid
+ *               (error message was generated)
+ *    #GNUNET_SYSERR on internal error
+ *               (we could not even queue an error message,
+ *                close HTTP session with MHD_NO)
+ */
+int
+TALER_MHD_parse_post_json (struct MHD_Connection *connection,
+                           void **con_cls,
+                           const char *upload_data,
+                           size_t *upload_data_size,
+                           json_t **json);
+
+
+/**
+ * Function called whenever we are done with a request
+ * to clean up our state.
+ *
+ * @param con_cls value as it was left by
+ *        #TALER_MHD_post_json(), to be cleaned up
+ */
+void
+TALER_MHD_parse_post_cleanup_callback (void *con_cls);
+
+
+/**
+ * Parse JSON object into components based on the given field
+ * specification.
+ *
+ * @param connection the connection to send an error response to
+ * @param root the JSON node to start the navigation at.
+ * @param spec field specification for the parser
+ * @return
+ *    #GNUNET_YES if navigation was successful (caller is responsible
+ *                for freeing allocated variable-size data using
+ *                GNUNET_JSON_parse_free() when done)
+ *    #GNUNET_NO if json is malformed, error response was generated
+ *    #GNUNET_SYSERR on internal error
+ */
+int
+TALER_MHD_parse_json_data (struct MHD_Connection *connection,
+                           const json_t *root,
+                           struct GNUNET_JSON_Specification *spec);
+
+
+/**
+ * Parse JSON array into components based on the given field
+ * specification.  Generates error response on parse errors.
+ *
+ * @param connection the connection to send an error response to
+ * @param root the JSON node to start the navigation at.
+ * @param[in,out] spec field specification for the parser
+ * @param ... -1-terminated list of array offsets of type 'int'
+ * @return
+ *    #GNUNET_YES if navigation was successful (caller is responsible
+ *                for freeing allocated variable-size data using
+ *                GNUNET_JSON_parse_free() when done)
+ *    #GNUNET_NO if json is malformed, error response was generated
+ *    #GNUNET_SYSERR on internal error
+ */
+int
+TALER_MHD_parse_json_array (struct MHD_Connection *connection,
+                            const json_t *root,
+                            struct GNUNET_JSON_Specification *spec,
+                            ...);
+
+
+/**
+ * Extraxt fixed-size base32crockford encoded data from request.
+ *
+ * Queues an error response to the connection if the parameter is missing or
+ * invalid.
+ *
+ * @param connection the MHD connection
+ * @param param_name the name of the parameter with the key
+ * @param[out] out_data pointer to store the result
+ * @param out_size expected size of @a out_data
+ * @return
+ *   #GNUNET_YES if the the argument is present
+ *   #GNUNET_NO if the argument is absent or malformed
+ *   #GNUNET_SYSERR on internal error (error response could not be sent)
+ */
+int
+TALER_MHD_parse_request_arg_data (struct MHD_Connection *connection,
+                                  const char *param_name,
+                                  void *out_data,
+                                  size_t out_size);
+
+
+/**
+ * Parse the configuration to determine on which port
+ * or UNIX domain path we should run an HTTP service.
+ *
+ * @param cfg configuration to parse
+ * @param section section of the configuration to parse (usually "exchange")
+ * @param[out] rport set to the port number, or 0 for none
+ * @param[out] unix_path set to the UNIX path, or NULL for none
+ * @param[out] unix_mode set to the mode to be used for @a unix_path
+ * @return #GNUNET_OK on success
+ */
+int
+TALER_MHD_parse_config (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                        const char *section,
+                        uint16_t *rport,
+                        char **unix_path,
+                        mode_t *unix_mode);
+
+
+/**
+ * Function called for logging by MHD.
+ *
+ * @param cls closure, NULL
+ * @param fm format string (`printf()`-style)
+ * @param ap arguments to @a fm
+ */
+void
+TALER_MHD_handle_logs (void *cls,
+                       const char *fm,
+                       va_list ap);
+
+
+/**
+ * Open UNIX domain socket for listining at @a unix_path with
+ * permissions @a unix_mode.
+ *
+ * @param unix_path where to listen
+ * @param unix_mode access permissions to set
+ * @return -1 on error, otherwise the listen socket
+ */
+int
+TALER_MHD_open_unix_path (const char *unix_path,
+                          mode_t unix_mode);
+
+
+/**
+ * Bind a listen socket to the UNIX domain path
+ * or the TCP port and IP address as specified
+ * in @a cfg in section @a section.  IF only a
+ * port was specified, set @a port and return -1.
+ * Otherwise, return the bound file descriptor.
+ *
+ * @param cfg configuration to parse
+ * @param section configuration section to use
+ * @param port[out] port to set, if TCP without BINDTO
+ * @return -1 and a port of zero on error, otherwise
+ *    either -1 and a port, or a bound stream socket
+ */
+int
+TALER_MHD_bind (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                const char *section,
+                uint16_t *port);
+
+#endif
diff --git a/src/json/json.c b/src/json/json.c
index 90fe3dd4f..8d4089795 100644
--- a/src/json/json.c
+++ b/src/json/json.c
@@ -80,4 +80,33 @@ TALER_JSON_get_error_code (const json_t *json)
 }
 
 
+/**
+ * Extract the Taler error code from the given @a data object, which is expected to be in JSON.
+ * Note that #TALER_EC_INVALID is returned if no "code" is present or if @a data is not in JSON.
+ *
+ * @param data response to extract the error code from
+ * @param data_size number of bytes in @a data
+ * @return the "code" value from @a json
+ */
+enum TALER_ErrorCode
+TALER_JSON_get_error_code2 (const void *data,
+                            size_t data_size)
+{
+  json_t *json;
+  enum TALER_ErrorCode ec;
+  json_error_t err;
+
+  json = json_loads (data,
+                     data_size,
+                     &err);
+  if (NULL == json)
+    return TALER_EC_INVALID;
+  ec = TALER_JSON_get_error_code (json);
+  json_decref (json);
+  if (ec == TALER_EC_NONE)
+    return TALER_EC_INVALID;
+  return ec;
+}
+
+
 /* End of json/json.c */
diff --git a/src/lib/auditor_api_deposit_confirmation.c b/src/lib/auditor_api_deposit_confirmation.c
index f221b7fd7..73173cc31 100644
--- a/src/lib/auditor_api_deposit_confirmation.c
+++ b/src/lib/auditor_api_deposit_confirmation.c
@@ -99,7 +99,7 @@ handle_deposit_confirmation_finished (void *cls,
     /* This should never happen, either us or the auditor is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, auditor says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/exchange_api_curl_defaults.c b/src/lib/exchange_api_curl_defaults.c
index 36d1edf7b..7b642bc89 100644
--- a/src/lib/exchange_api_curl_defaults.c
+++ b/src/lib/exchange_api_curl_defaults.c
@@ -35,7 +35,6 @@ TEL_curl_easy_get (const char *url)
   CURL *eh;
 
   eh = curl_easy_init ();
-
   GNUNET_assert (CURLE_OK ==
                  curl_easy_setopt (eh,
                                    CURLOPT_URL,
diff --git a/src/lib/exchange_api_deposit.c b/src/lib/exchange_api_deposit.c
index 48f9a06bb..30bb6c976 100644
--- a/src/lib/exchange_api_deposit.c
+++ b/src/lib/exchange_api_deposit.c
@@ -325,7 +325,7 @@ handle_deposit_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_FORBIDDEN:
+  case MHD_HTTP_CONFLICT:
     /* Double spending; check signatures on transaction history */
     if (GNUNET_OK !=
         verify_deposit_signature_forbidden (dh,
@@ -335,7 +335,7 @@ handle_deposit_finished (void *cls,
       response_code = 0;
     }
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/exchange_api_payback.c b/src/lib/exchange_api_payback.c
index 912548cfe..f9df27e7a 100644
--- a/src/lib/exchange_api_payback.c
+++ b/src/lib/exchange_api_payback.c
@@ -226,7 +226,7 @@ handle_payback_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_FORBIDDEN:
+  case MHD_HTTP_CONFLICT:
     {
       /* Insufficient funds, proof attached */
       json_t *history;
@@ -256,7 +256,7 @@ handle_payback_finished (void *cls,
       TALER_EXCHANGE_payback_cancel (ph);
       return;
     }
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/exchange_api_refresh.c b/src/lib/exchange_api_refresh.c
index db3692bcd..a75baec86 100644
--- a/src/lib/exchange_api_refresh.c
+++ b/src/lib/exchange_api_refresh.c
@@ -939,7 +939,7 @@ verify_refresh_melt_signature_ok (struct TALER_EXCHANGE_RefreshMeltHandle *rmh,
 
 
 /**
- * Verify that the signatures on the "403 FORBIDDEN" response from the
+ * Verify that the signatures on the "409 CONFLICT" response from the
  * exchange demonstrating customer double-spending are valid.
  *
  * @param rmh melt handle
@@ -947,9 +947,9 @@ verify_refresh_melt_signature_ok (struct TALER_EXCHANGE_RefreshMeltHandle *rmh,
  * @return #GNUNET_OK if the signature(s) is valid, #GNUNET_SYSERR if not
  */
 static int
-verify_refresh_melt_signature_forbidden (struct
-                                         TALER_EXCHANGE_RefreshMeltHandle *rmh,
-                                         const json_t *json)
+verify_refresh_melt_signature_conflict (struct
+                                        TALER_EXCHANGE_RefreshMeltHandle *rmh,
+                                        const json_t *json)
 {
   json_t *history;
   struct TALER_Amount original_value;
@@ -1083,17 +1083,17 @@ handle_refresh_melt_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_FORBIDDEN:
+  case MHD_HTTP_CONFLICT:
     /* Double spending; check signatures on transaction history */
     if (GNUNET_OK !=
-        verify_refresh_melt_signature_forbidden (rmh,
-                                                 j))
+        verify_refresh_melt_signature_conflict (rmh,
+                                                j))
     {
       GNUNET_break_op (0);
       response_code = 0;
     }
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; assuming we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/exchange_api_refund.c b/src/lib/exchange_api_refund.c
index e8ae6b74a..b8c422e88 100644
--- a/src/lib/exchange_api_refund.c
+++ b/src/lib/exchange_api_refund.c
@@ -169,7 +169,7 @@ handle_refund_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/exchange_api_reserve.c b/src/lib/exchange_api_reserve.c
index a57d4e9dc..2c62cac20 100644
--- a/src/lib/exchange_api_reserve.c
+++ b/src/lib/exchange_api_reserve.c
@@ -797,7 +797,7 @@ reserve_withdraw_ok (struct TALER_EXCHANGE_ReserveWithdrawHandle *wsh,
 
 
 /**
- * We got a 403 FORBIDDEN response for the /reserve/withdraw operation.
+ * We got a 409 CONFLICT response for the /reserve/withdraw operation.
  * Check the signatures on the withdraw transactions in the provided
  * history and that the balances add up.  We don't do anything directly
  * with the information, as the JSON will be returned to the application.
@@ -941,7 +941,7 @@ handle_reserve_withdraw_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_FORBIDDEN:
+  case MHD_HTTP_CONFLICT:
     /* The exchange says that the reserve has insufficient funds;
        check the signatures in the history... */
     if (GNUNET_OK !=
@@ -952,7 +952,7 @@ handle_reserve_withdraw_finished (void *cls,
       response_code = 0;
     }
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     GNUNET_break (0);
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
diff --git a/src/lib/exchange_api_track_transaction.c b/src/lib/exchange_api_track_transaction.c
index 29b85facf..de3f98b65 100644
--- a/src/lib/exchange_api_track_transaction.c
+++ b/src/lib/exchange_api_track_transaction.c
@@ -217,7 +217,7 @@ handle_deposit_wtid_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/exchange_api_track_transfer.c b/src/lib/exchange_api_track_transfer.c
index 419998a2c..2c90bf199 100644
--- a/src/lib/exchange_api_track_transfer.c
+++ b/src/lib/exchange_api_track_transfer.c
@@ -279,7 +279,7 @@ handle_track_transfer_finished (void *cls,
     /* This should never happen, either us or the exchange is buggy
        (or API version conflict); just pass JSON reply to the application */
     break;
-  case MHD_HTTP_UNAUTHORIZED:
+  case MHD_HTTP_FORBIDDEN:
     /* Nothing really to verify, exchange says one of the signatures is
        invalid; as we checked them, this should never happen, we
        should pass the JSON reply to the application */
diff --git a/src/lib/test_auditor_api.conf b/src/lib/test_auditor_api.conf
index e01cbfcbd..3a12b3c5e 100644
--- a/src/lib/test_auditor_api.conf
+++ b/src/lib/test_auditor_api.conf
@@ -15,6 +15,8 @@ BASE_URL = "http://localhost:8083/"
 # HTTP port the auditor listens to
 PORT = 8083
 
+TINY_AMOUNT = EUR:0.01
+
 [exchange]
 
 # how long is one signkey valid?
diff --git a/src/lib/test_exchange_api.c b/src/lib/test_exchange_api.c
index 23a52be1f..4e8eb7e09 100644
--- a/src/lib/test_exchange_api.c
+++ b/src/lib/test_exchange_api.c
@@ -228,7 +228,7 @@ run (void *cls,
     TALER_TESTING_cmd_withdraw_amount ("withdraw-coin-2",
                                        "create-reserve-1",
                                        "EUR:5",
-                                       MHD_HTTP_FORBIDDEN),
+                                       MHD_HTTP_CONFLICT),
 
     /**
      * Try to double spend using different wire details.
@@ -238,7 +238,7 @@ run (void *cls,
       TALER_TESTING_make_wire_details (43,
                                        fakebank_url),
       "{\"items\":[{\"name\":\"ice cream\",\"value\":1}]}",
-      GNUNET_TIME_UNIT_ZERO, "EUR:5", MHD_HTTP_FORBIDDEN),
+      GNUNET_TIME_UNIT_ZERO, "EUR:5", MHD_HTTP_CONFLICT),
 
     /**
      * Try to double spend using a different transaction id.
@@ -253,7 +253,7 @@ run (void *cls,
       TALER_TESTING_make_wire_details (43,
                                        fakebank_url),
       "{\"items\":[{\"name\":\"ice cream\",\"value\":1}]}",
-      GNUNET_TIME_UNIT_ZERO, "EUR:5", MHD_HTTP_FORBIDDEN),
+      GNUNET_TIME_UNIT_ZERO, "EUR:5", MHD_HTTP_CONFLICT),
 
     /**
      * Try to double spend with different proposal.
@@ -263,7 +263,7 @@ run (void *cls,
       TALER_TESTING_make_wire_details (43,
                                        fakebank_url),
       "{\"items\":[{\"name\":\"ice cream\",\"value\":2}]}",
-      GNUNET_TIME_UNIT_ZERO, "EUR:5", MHD_HTTP_FORBIDDEN),
+      GNUNET_TIME_UNIT_ZERO, "EUR:5", MHD_HTTP_CONFLICT),
 
     TALER_TESTING_cmd_end ()
   };
@@ -364,7 +364,7 @@ run (void *cls,
     TALER_TESTING_cmd_refresh_melt
       ("refresh-melt-failing",
       "refresh-withdraw-coin-1",
-      MHD_HTTP_FORBIDDEN,
+      MHD_HTTP_CONFLICT,
       NULL),
 
     /* FIXME: also test with coin that was already melted
@@ -708,7 +708,7 @@ run (void *cls,
       ("payback-withdraw-coin-2-over",
       "payback-create-reserve-1",
       "EUR:10",
-      MHD_HTTP_FORBIDDEN),
+      MHD_HTTP_CONFLICT),
 
     TALER_TESTING_cmd_status ("payback-reserve-status-2",
                               "payback-create-reserve-1",
@@ -740,7 +740,7 @@ run (void *cls,
       ("expired-withdraw",
       "short-lived-reserve",
       "EUR:1",
-      MHD_HTTP_FORBIDDEN),
+      MHD_HTTP_CONFLICT),
 
     TALER_TESTING_cmd_check_bank_transfer
       ("check_bank_short-lived_transfer",
@@ -798,7 +798,7 @@ run (void *cls,
                                "EUR:0.5",
                                NULL),
 
-    TALER_TESTING_cmd_payback ("payback-2b", MHD_HTTP_FORBIDDEN,
+    TALER_TESTING_cmd_payback ("payback-2b", MHD_HTTP_CONFLICT,
                                "payback-withdraw-coin-2a",
                                "EUR:0.5",
                                NULL),
diff --git a/src/lib/test_exchange_api_twisted.c b/src/lib/test_exchange_api_twisted.c
index 739669b97..f648b871d 100644
--- a/src/lib/test_exchange_api_twisted.c
+++ b/src/lib/test_exchange_api_twisted.c
@@ -16,9 +16,8 @@
   License along with TALER; see the file COPYING.  If not, see
   <http://www.gnu.org/licenses/>
 */
-
 /**
- * @file exchange/test_exchange_api_twister.c
+ * @file exchange/test_exchange_api_twisted.c
  * @brief testcase to test exchange's HTTP API interface
  * @author Marcello Stanisci
  * @author Sree Harsha Totakura <sreeharsha@totakura.in>
@@ -262,7 +261,7 @@ run (void *cls,
 
     TALER_TESTING_cmd_refund
       ("refund-bad-sig",
-      MHD_HTTP_UNAUTHORIZED,
+      MHD_HTTP_FORBIDDEN,
       "EUR:5",
       "EUR:0.01",
       "deposit-refund-1"),
@@ -285,7 +284,7 @@ run (void *cls,
       "\"value\":\"EUR:5\"}]}",
       GNUNET_TIME_UNIT_MINUTES,
       "EUR:5",
-      MHD_HTTP_FORBIDDEN),
+      MHD_HTTP_CONFLICT),
 
     TALER_TESTING_cmd_refund
       ("refund-deposit-not-found",
@@ -350,7 +349,7 @@ main (int argc,
   /* These environment variables get in the way... */
   unsetenv ("XDG_DATA_HOME");
   unsetenv ("XDG_CONFIG_HOME");
-  GNUNET_log_setup ("test-exchange-api-new-twisted",
+  GNUNET_log_setup ("test-exchange-api-twisted",
                     "DEBUG", NULL);
 
   if (NULL == (fakebank_url = TALER_TESTING_prepare_fakebank
diff --git a/src/mhd/Makefile.am b/src/mhd/Makefile.am
new file mode 100644
index 000000000..cc4c70735
--- /dev/null
+++ b/src/mhd/Makefile.am
@@ -0,0 +1,26 @@
+# This Makefile.am is in the public domain
+AM_CPPFLAGS = -I$(top_srcdir)/src/include
+
+if USE_COVERAGE
+  AM_CFLAGS = --coverage -O0
+  XLIB = -lgcov
+endif
+
+lib_LTLIBRARIES = \
+  libtalermhd.la
+
+libtalermhd_la_SOURCES = \
+  mhd_config.c \
+  mhd_parsing.c \
+  mhd_responses.c 
+libtalermhd_la_LDFLAGS = \
+  -version-info 0:0:0 \
+  -export-dynamic -no-undefined
+libtalermhd_la_LIBADD = \
+  -lgnunetjson \
+  $(top_builddir)/src/json/libtalerjson.la \
+  $(top_builddir)/src/util/libtalerutil.la \
+  -lgnunetutil \
+  -ljansson \
+  $(XLIB)
+
diff --git a/src/mhd/mhd_config.c b/src/mhd/mhd_config.c
new file mode 100644
index 000000000..d4b0e9795
--- /dev/null
+++ b/src/mhd/mhd_config.c
@@ -0,0 +1,396 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014--2019 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file mhd_config.c
+ * @brief functions to configure and setup MHD
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_mhd_lib.h"
+
+
+/**
+ * Backlog for listen operation on UNIX domain sockets.
+ */
+#define UNIX_BACKLOG 500
+
+
+/**
+ * Parse the configuration to determine on which port
+ * or UNIX domain path we should run an HTTP service.
+ *
+ * @param cfg configuration to parse
+ * @param section section of the configuration to parse (usually "exchange")
+ * @param[out] rport set to the port number, or 0 for none
+ * @param[out] unix_path set to the UNIX path, or NULL for none
+ * @param[out] unix_mode set to the mode to be used for @a unix_path
+ * @return #GNUNET_OK on success
+ */
+int
+TALER_MHD_parse_config (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                        const char *section,
+                        uint16_t *rport,
+                        char **unix_path,
+                        mode_t *unix_mode)
+{
+  const char *choices[] = {"tcp", "unix"};
+  const char *serve_type;
+  unsigned long long port;
+
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_choice (cfg,
+                                             section,
+                                             "serve",
+                                             choices,
+                                             &serve_type))
+  {
+    GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                               section,
+                               "serve",
+                               "serve type required");
+    return GNUNET_SYSERR;
+  }
+
+  if (0 == strcasecmp (serve_type, "tcp"))
+  {
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_number (cfg,
+                                               section,
+                                               "port",
+                                               &port))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "port",
+                                 "port number required");
+      return GNUNET_SYSERR;
+    }
+
+    if ( (0 == port) ||
+         (port > UINT16_MAX) )
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "port",
+                                 "value not in [1,65535]");
+      return GNUNET_SYSERR;
+    }
+    *rport = (uint16_t) port;
+    *unix_path = NULL;
+    return GNUNET_OK;
+  }
+  if (0 == strcmp (serve_type, "unix"))
+  {
+    struct sockaddr_un s_un;
+    char *modestring;
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                                 section,
+                                                 "unixpath",
+                                                 unix_path))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "unixpath",
+                                 "unixpath required");
+      return GNUNET_SYSERR;
+    }
+    if (strlen (*unix_path) >= sizeof (s_un.sun_path))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "unixpath `%s' is too long\n",
+                  *unix_path);
+      return GNUNET_SYSERR;
+    }
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_string (cfg,
+                                               section,
+                                               "UNIXPATH_MODE",
+                                               &modestring))
+    {
+      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "UNIXPATH_MODE");
+      return GNUNET_SYSERR;
+    }
+    errno = 0;
+    *unix_mode = (mode_t) strtoul (modestring, NULL, 8);
+    if (0 != errno)
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 section,
+                                 "UNIXPATH_MODE",
+                                 "must be octal number");
+      GNUNET_free (modestring);
+      return GNUNET_SYSERR;
+    }
+    GNUNET_free (modestring);
+    return GNUNET_OK;
+  }
+  /* not reached */
+  GNUNET_assert (0);
+  return GNUNET_SYSERR;
+}
+
+
+/**
+ * Function called for logging by MHD.
+ *
+ * @param cls closure, NULL
+ * @param fm format string (`printf()`-style)
+ * @param ap arguments to @a fm
+ */
+void
+TALER_MHD_handle_logs (void *cls,
+                       const char *fm,
+                       va_list ap)
+{
+  static int cache;
+  char buf[2048];
+
+  (void) cls;
+  if (-1 == cache)
+    return;
+  if (0 == cache)
+  {
+    if (0 ==
+        GNUNET_get_log_call_status (GNUNET_ERROR_TYPE_INFO,
+                                    "libmicrohttpd",
+                                    __FILE__,
+                                    __FUNCTION__,
+                                    __LINE__))
+    {
+      cache = -1;
+      return;
+    }
+  }
+  cache = 1;
+  vsnprintf (buf,
+             sizeof (buf),
+             fm,
+             ap);
+  GNUNET_log_from_nocheck (GNUNET_ERROR_TYPE_INFO,
+                           "libmicrohttpd",
+                           "%s",
+                           buf);
+}
+
+
+/**
+ * Open UNIX domain socket for listining at @a unix_path with
+ * permissions @a unix_mode.
+ *
+ * @param unix_path where to listen
+ * @param unix_mode access permissions to set
+ * @return -1 on error, otherwise the listen socket
+ */
+int
+TALER_MHD_open_unix_path (const char *unix_path,
+                          mode_t unix_mode)
+{
+  struct GNUNET_NETWORK_Handle *nh;
+  struct sockaddr_un *un;
+  int fd;
+
+  if (sizeof (un->sun_path) <= strlen (unix_path))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "unixpath `%s' is too long\n",
+                unix_path);
+    return -1;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Creating listen socket '%s' with mode %o\n",
+              unix_path,
+              unix_mode);
+
+  if (GNUNET_OK !=
+      GNUNET_DISK_directory_create_for_file (unix_path))
+  {
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
+                              "mkdir",
+                              unix_path);
+  }
+
+  un = GNUNET_new (struct sockaddr_un);
+  un->sun_family = AF_UNIX;
+  strncpy (un->sun_path,
+           unix_path,
+           sizeof (un->sun_path) - 1);
+  GNUNET_NETWORK_unix_precheck (un);
+
+  if (NULL == (nh = GNUNET_NETWORK_socket_create (AF_UNIX,
+                                                  SOCK_STREAM,
+                                                  0)))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "socket");
+    GNUNET_free (un);
+    return -1;
+  }
+  if (GNUNET_OK !=
+      GNUNET_NETWORK_socket_bind (nh,
+                                  (void *) un,
+                                  sizeof (struct sockaddr_un)))
+  {
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
+                              "bind",
+                              unix_path);
+    GNUNET_free (un);
+    GNUNET_NETWORK_socket_close (nh);
+    return -1;
+  }
+  GNUNET_free (un);
+  if (GNUNET_OK !=
+      GNUNET_NETWORK_socket_listen (nh,
+                                    UNIX_BACKLOG))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "listen");
+    GNUNET_NETWORK_socket_close (nh);
+    return -1;
+  }
+
+  if (0 != chmod (unix_path,
+                  unix_mode))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "chmod");
+    GNUNET_NETWORK_socket_close (nh);
+    return -1;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "set socket '%s' to mode %o\n",
+              unix_path,
+              unix_mode);
+  fd = GNUNET_NETWORK_get_fd (nh);
+  GNUNET_NETWORK_socket_free_memory_only_ (nh);
+  return fd;
+}
+
+
+/**
+ * Bind a listen socket to the UNIX domain path
+ * or the TCP port and IP address as specified
+ * in @a cfg in section @a section.  IF only a
+ * port was specified, set @a port and return -1.
+ * Otherwise, return the bound file descriptor.
+ *
+ * @param cfg configuration to parse
+ * @param section configuration section to use
+ * @param port[out] port to set, if TCP without BINDTO
+ * @return -1 and a port of zero on error, otherwise
+ *    either -1 and a port, or a bound stream socket
+ */
+int
+TALER_MHD_bind (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                const char *section,
+                uint16_t *port)
+{
+  char *bind_to;
+  char *serve_unixpath;
+  mode_t unixpath_mode;
+  int fh;
+  char port_str[6];
+  struct addrinfo hints;
+  struct addrinfo *res;
+  int ec;
+  struct GNUNET_NETWORK_Handle *nh;
+
+  *port = 0;
+  if (GNUNET_OK !=
+      TALER_MHD_parse_config (cfg,
+                              section,
+                              port,
+                              &serve_unixpath,
+                              &unixpath_mode))
+    return -1;
+  if (NULL != serve_unixpath)
+    return TALER_MHD_open_unix_path (serve_unixpath,
+                                     unixpath_mode);
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_string (cfg,
+                                             section,
+                                             "BIND_TO",
+                                             &bind_to))
+    return -1; /* only set port */
+  /* let's have fun binding... */
+  GNUNET_snprintf (port_str,
+                   sizeof (port_str),
+                   "%u",
+                   (unsigned int) *port);
+  *port = 0; /* do NOT return port in case of errors */
+  memset (&hints, 0, sizeof (hints));
+  hints.ai_family = AF_UNSPEC;
+  hints.ai_socktype = SOCK_STREAM;
+  hints.ai_protocol = IPPROTO_TCP;
+  hints.ai_flags = AI_PASSIVE
+#ifdef AI_IDN
+                   | AI_IDN
+#endif
+  ;
+  if (0 !=
+      (ec = getaddrinfo (bind_to,
+                         port_str,
+                         &hints,
+                         &res)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to resolve BIND_TO address `%s': %s\n",
+                bind_to,                  gai_strerror (ec));
+    GNUNET_free (bind_to);
+    return -1;
+  }
+  GNUNET_free (bind_to);
+
+  if (NULL == (nh = GNUNET_NETWORK_socket_create (res->ai_family,
+                                                  res->ai_socktype,
+                                                  res->ai_protocol)))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "socket");
+    freeaddrinfo (res);
+    return -1;
+  }
+  if (GNUNET_OK !=
+      GNUNET_NETWORK_socket_bind (nh,
+                                  res->ai_addr,
+                                  res->ai_addrlen))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "bind");
+    freeaddrinfo (res);
+    return -1;
+  }
+  freeaddrinfo (res);
+  if (GNUNET_OK !=
+      GNUNET_NETWORK_socket_listen (nh,
+                                    UNIX_BACKLOG))
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "listen");
+    GNUNET_SCHEDULER_shutdown ();
+    return -1;
+  }
+  fh = GNUNET_NETWORK_get_fd (nh);
+  GNUNET_NETWORK_socket_free_memory_only_ (nh);
+  return fh;
+}
diff --git a/src/exchange/taler-exchange-httpd_parsing.c b/src/mhd/mhd_parsing.c
index fb8932b9a..0b070ffe5 100644
--- a/src/exchange/taler-exchange-httpd_parsing.c
+++ b/src/mhd/mhd_parsing.c
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014, 2015, 2016 GNUnet e.V.
+  Copyright (C) 2014--2019 Taler Systems SA
 
   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU Affero General Public License as published by the Free Software
@@ -13,21 +13,18 @@
   You should have received a copy of the GNU Affero General Public License along with
   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */
-
 /**
- * @file taler-exchange-httpd_parsing.c
+ * @file mhd_parsing.c
  * @brief functions to parse incoming requests (MHD arguments and JSON snippets)
  * @author Florian Dold
  * @author Benedikt Mueller
  * @author Christian Grothoff
  */
-
 #include "platform.h"
 #include <gnunet/gnunet_util_lib.h>
 #include <gnunet/gnunet_json_lib.h>
 #include "taler_json_lib.h"
-#include "taler-exchange-httpd_parsing.h"
-#include "taler-exchange-httpd_responses.h"
+#include "taler_mhd_lib.h"
 
 
 /**
@@ -41,7 +38,7 @@
  * realizes an MHD POST processor that will (incrementally) process
  * JSON data uploaded to the HTTP server.  It will store the required
  * state in the @a con_cls, which must be cleaned up using
- * #TEH_PARSE_post_cleanup_callback().
+ * #TALER_MHD_post_cleanup_callback().
  *
  * @param connection the MHD connection
  * @param con_cls the closure (points to a `struct Buffer *`)
@@ -60,11 +57,11 @@
  *                close HTTP session with MHD_NO)
  */
 int
-TEH_PARSE_post_json (struct MHD_Connection *connection,
-                     void **con_cls,
-                     const char *upload_data,
-                     size_t *upload_data_size,
-                     json_t **json)
+TALER_MHD_parse_post_json (struct MHD_Connection *connection,
+                           void **con_cls,
+                           const char *upload_data,
+                           size_t *upload_data_size,
+                           json_t **json)
 {
   enum GNUNET_JSON_PostResult pr;
 
@@ -76,23 +73,26 @@ TEH_PARSE_post_json (struct MHD_Connection *connection,
                                 json);
   switch (pr)
   {
-
   case GNUNET_JSON_PR_OUT_OF_MEMORY:
-    return (MHD_NO == TEH_RESPONSE_reply_internal_error
+    return (MHD_NO ==
+            TALER_MHD_reply_with_error
               (connection,
+              MHD_HTTP_INTERNAL_SERVER_ERROR,
               TALER_EC_PARSER_OUT_OF_MEMORY,
               "out of memory")) ? GNUNET_SYSERR : GNUNET_NO;
 
   case GNUNET_JSON_PR_CONTINUE:
     return GNUNET_YES;
-
   case GNUNET_JSON_PR_REQUEST_TOO_LARGE:
-    return (MHD_NO == TEH_RESPONSE_reply_request_too_large
+    return (MHD_NO ==
+            TALER_MHD_reply_request_too_large
               (connection)) ? GNUNET_SYSERR : GNUNET_NO;
-
   case GNUNET_JSON_PR_JSON_INVALID:
     return (MHD_YES ==
-            TEH_RESPONSE_reply_invalid_json (connection))
+            TALER_MHD_reply_with_error (connection,
+                                        MHD_HTTP_BAD_REQUEST,
+                                        TALER_EC_JSON_INVALID,
+                                        "invalid JSON uploaded"))
            ? GNUNET_NO : GNUNET_SYSERR;
   case GNUNET_JSON_PR_SUCCESS:
     GNUNET_break (NULL != *json);
@@ -109,11 +109,12 @@ TEH_PARSE_post_json (struct MHD_Connection *connection,
  * to clean up our state.
  *
  * @param con_cls value as it was left by
- *        #TEH_PARSE_post_json(), to be cleaned up
+ *        #TALER_MHD_post_json(), to be cleaned up
  */
 void
-TEH_PARSE_post_cleanup_callback (void *con_cls)
+TALER_MHD_parse_post_cleanup_callback (void *con_cls)
 {
+  // FIXME: this should probably NOT be done with a 'void *' like this!
   GNUNET_JSON_post_parser_cleanup (con_cls);
 }
 
@@ -134,10 +135,10 @@ TEH_PARSE_post_cleanup_callback (void *con_cls)
  *   #GNUNET_SYSERR on internal error (error response could not be sent)
  */
 int
-TEH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
-                                const char *param_name,
-                                void *out_data,
-                                size_t out_size)
+TALER_MHD_parse_request_arg_data (struct MHD_Connection *connection,
+                                  const char *param_name,
+                                  void *out_data,
+                                  size_t out_size)
 {
   const char *str;
 
@@ -147,9 +148,10 @@ TEH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
   if (NULL == str)
   {
     return (MHD_NO ==
-            TEH_RESPONSE_reply_arg_missing (connection,
-                                            TALER_EC_PARAMETER_MISSING,
-                                            param_name))
+            TALER_MHD_reply_with_error (connection,
+                                        MHD_HTTP_BAD_REQUEST,
+                                        TALER_EC_PARAMETER_MISSING,
+                                        param_name))
            ? GNUNET_SYSERR : GNUNET_NO;
   }
   if (GNUNET_OK !=
@@ -158,9 +160,10 @@ TEH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
                                      out_data,
                                      out_size))
     return (MHD_NO ==
-            TEH_RESPONSE_reply_arg_invalid (connection,
-                                            TALER_EC_PARAMETER_MALFORMED,
-                                            param_name))
+            TALER_MHD_reply_with_error (connection,
+                                        MHD_HTTP_BAD_REQUEST,
+                                        TALER_EC_PARAMETER_MALFORMED,
+                                        param_name))
            ? GNUNET_SYSERR : GNUNET_NO;
   return GNUNET_OK;
 }
@@ -181,9 +184,9 @@ TEH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
  *    #GNUNET_SYSERR on internal error
  */
 int
-TEH_PARSE_json_data (struct MHD_Connection *connection,
-                     const json_t *root,
-                     struct GNUNET_JSON_Specification *spec)
+TALER_MHD_parse_json_data (struct MHD_Connection *connection,
+                           const json_t *root,
+                           struct GNUNET_JSON_Specification *spec)
 {
   int ret;
   const char *error_json_name;
@@ -198,15 +201,15 @@ TEH_PARSE_json_data (struct MHD_Connection *connection,
     if (NULL == error_json_name)
       error_json_name = "<no field>";
     ret = (MHD_YES ==
-           TEH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         "{s:s, s:I, s:s, s:I}",
-                                         "error", "parse error",
-                                         "code",
-                                         (json_int_t)
-                                         TALER_EC_JSON_INVALID_WITH_DETAILS,
-                                         "field", error_json_name,
-                                         "line", (json_int_t) error_line))
+           TALER_MHD_reply_json_pack (connection,
+                                      MHD_HTTP_BAD_REQUEST,
+                                      "{s:s, s:I, s:s, s:I}",
+                                      "hint", "JSON parse error",
+                                      "code",
+                                      (json_int_t)
+                                      TALER_EC_JSON_INVALID_WITH_DETAILS,
+                                      "field", error_json_name,
+                                      "line", (json_int_t) error_line))
           ? GNUNET_NO : GNUNET_SYSERR;
     return ret;
   }
@@ -230,10 +233,10 @@ TEH_PARSE_json_data (struct MHD_Connection *connection,
  *    #GNUNET_SYSERR on internal error
  */
 int
-TEH_PARSE_json_array (struct MHD_Connection *connection,
-                      const json_t *root,
-                      struct GNUNET_JSON_Specification *spec,
-                      ...)
+TALER_MHD_parse_json_array (struct MHD_Connection *connection,
+                            const json_t *root,
+                            struct GNUNET_JSON_Specification *spec,
+                            ...)
 {
   int ret;
   const char *error_json_name;
@@ -253,11 +256,14 @@ TEH_PARSE_json_array (struct MHD_Connection *connection,
   if (NULL == root)
   {
     ret = (MHD_YES ==
-           TEH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         "{s:s, s:I}",
-                                         "error", "parse error",
-                                         "dimension", dim))
+           TALER_MHD_reply_json_pack (connection,
+                                      MHD_HTTP_BAD_REQUEST,
+                                      "{s:s, s:I, s:I}",
+                                      "hint", "expected array",
+                                      "code",
+                                      (json_int_t)
+                                      TALER_EC_JSON_INVALID_WITH_DETAILS,
+                                      "dimension", dim))
           ? GNUNET_NO : GNUNET_SYSERR;
     return ret;
   }
@@ -270,12 +276,14 @@ TEH_PARSE_json_array (struct MHD_Connection *connection,
     if (NULL == error_json_name)
       error_json_name = "<no field>";
     ret = (MHD_YES ==
-           TEH_RESPONSE_reply_json_pack (connection,
-                                         MHD_HTTP_BAD_REQUEST,
-                                         "{s:s, s:s, s:I}",
-                                         "error", "parse error",
-                                         "field", error_json_name,
-                                         "line", (json_int_t) error_line))
+           TALER_MHD_reply_json_pack (connection,
+                                      MHD_HTTP_BAD_REQUEST,
+                                      "{s:s, s:I, s:I}",
+                                      "hint", error_json_name,
+                                      "code",
+                                      (json_int_t)
+                                      TALER_EC_JSON_INVALID_WITH_DETAILS,
+                                      "line", (json_int_t) error_line))
           ? GNUNET_NO : GNUNET_SYSERR;
     return ret;
   }
@@ -283,4 +291,4 @@ TEH_PARSE_json_array (struct MHD_Connection *connection,
 }
 
 
-/* end of taler-exchange-httpd_parsing.c */
+/* end of mhd_parsing.c */
diff --git a/src/mhd/mhd_responses.c b/src/mhd/mhd_responses.c
new file mode 100644
index 000000000..3642e7d54
--- /dev/null
+++ b/src/mhd/mhd_responses.c
@@ -0,0 +1,501 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2019 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file mhd_responses.c
+ * @brief API for generating HTTP replies
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <zlib.h>
+#include "taler_util.h"
+#include "taler_mhd_lib.h"
+
+
+/**
+ * Enable checking signatures before we hand them out
+ * (even though we should have checked them before).
+ * So technically these checks are redundant, but good
+ * during testing.
+ */
+#define SANITY_CHECKS_ON 1
+
+
+/**
+ * Global options for response generation.
+ */
+static enum TALER_MHD_GlobalOptions TM_go;
+
+
+/**
+ * Set global options for response generation
+ * within libtalermhd.
+ *
+ * @param go global options to use
+ */
+void
+TALER_MHD_setup (enum TALER_MHD_GlobalOptions go)
+{
+  TM_go = go;
+}
+
+
+/**
+ * Add headers we want to return in every response.
+ * Useful for testing, like if we want to always close
+ * connections.
+ *
+ * @param response response to modify
+ */
+void
+TALER_MHD_add_global_headers (struct MHD_Response *response)
+{
+  if (0 != (TM_go & TALER_MHD_GO_FORCE_CONNECTION_CLOSE))
+    GNUNET_break (MHD_YES ==
+                  MHD_add_response_header (response,
+                                           MHD_HTTP_HEADER_CONNECTION,
+                                           "close"));
+}
+
+
+/**
+ * Is HTTP body deflate compression supported by the client?
+ *
+ * @param connection connection to check
+ * @return #MHD_YES if 'deflate' compression is allowed
+ *
+ * Note that right now we're ignoring q-values, which is technically
+ * not correct, and also do not support "*" anywhere but in a line by
+ * itself.  This should eventually be fixed, see also
+ * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
+ */
+int
+TALER_MHD_can_compress (struct MHD_Connection *connection)
+{
+  const char *ae;
+  const char *de;
+
+  if (0 != (TM_go & TALER_MHD_GO_DISABLE_COMPRESSION))
+    return MHD_NO;
+  ae = MHD_lookup_connection_value (connection,
+                                    MHD_HEADER_KIND,
+                                    MHD_HTTP_HEADER_ACCEPT_ENCODING);
+  if (NULL == ae)
+    return MHD_NO;
+  if (0 == strcmp (ae,
+                   "*"))
+    return MHD_YES;
+  de = strstr (ae,
+               "deflate");
+  if (NULL == de)
+    return MHD_NO;
+  if ( ( (de == ae) ||
+         (de[-1] == ',') ||
+         (de[-1] == ' ') ) &&
+       ( (de[strlen ("deflate")] == '\0') ||
+         (de[strlen ("deflate")] == ',') ||
+         (de[strlen ("deflate")] == ';') ) )
+    return MHD_YES;
+  return MHD_NO;
+}
+
+
+/**
+ * Try to compress a response body.  Updates @a buf and @a buf_size.
+ *
+ * @param[in,out] buf pointer to body to compress
+ * @param[in,out] buf_size pointer to initial size of @a buf
+ * @return #MHD_YES if @a buf was compressed
+ */
+int
+TALER_MHD_body_compress (void **buf,
+                         size_t *buf_size)
+{
+  Bytef *cbuf;
+  uLongf cbuf_size;
+  int ret;
+
+  cbuf_size = compressBound (*buf_size);
+  cbuf = malloc (cbuf_size);
+  if (NULL == cbuf)
+    return MHD_NO;
+  ret = compress (cbuf,
+                  &cbuf_size,
+                  (const Bytef *) *buf,
+                  *buf_size);
+  if ( (Z_OK != ret) ||
+       (cbuf_size >= *buf_size) )
+  {
+    /* compression failed */
+    free (cbuf);
+    return MHD_NO;
+  }
+  free (*buf);
+  *buf = (void *) cbuf;
+  *buf_size = (size_t) cbuf_size;
+  return MHD_YES;
+}
+
+
+/**
+ * Make JSON response object.
+ *
+ * @param json the json object
+ * @return MHD response object
+ */
+struct MHD_Response *
+TALER_MHD_make_json (const json_t *json)
+{
+  struct MHD_Response *resp;
+  char *json_str;
+
+  json_str = json_dumps (json,
+                         JSON_INDENT (2));
+  if (NULL == json_str)
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  resp = MHD_create_response_from_buffer (strlen (json_str),
+                                          json_str,
+                                          MHD_RESPMEM_MUST_FREE);
+  if (NULL == resp)
+  {
+    free (json_str);
+    GNUNET_break (0);
+    return NULL;
+  }
+  TALER_MHD_add_global_headers (resp);
+  GNUNET_break (MHD_YES ==
+                MHD_add_response_header (resp,
+                                         MHD_HTTP_HEADER_CONTENT_TYPE,
+                                         "application/json"));
+  return resp;
+}
+
+
+/**
+ * Send JSON object as response.
+ *
+ * @param connection the MHD connection
+ * @param json the json object
+ * @param response_code the http response code
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json (struct MHD_Connection *connection,
+                      const json_t *json,
+                      unsigned int response_code)
+{
+  struct MHD_Response *resp;
+  void *json_str;
+  size_t json_len;
+  int ret;
+  int comp;
+
+  json_str = json_dumps (json,
+                         JSON_INDENT (2));
+  if (NULL == json_str)
+  {
+    /**
+     * This log helps to figure out which
+     * function called this one and assert-failed.
+     */
+    TALER_LOG_ERROR ("Aborting json-packing for HTTP code: %u\n",
+                     response_code);
+
+    GNUNET_assert (0);
+    return MHD_NO;
+  }
+  json_len = strlen (json_str);
+  /* try to compress the body */
+  comp = MHD_NO;
+  if (MHD_YES ==
+      TALER_MHD_can_compress (connection))
+    comp = TALER_MHD_body_compress (&json_str,
+                                    &json_len);
+  resp = MHD_create_response_from_buffer (json_len,
+                                          json_str,
+                                          MHD_RESPMEM_MUST_FREE);
+  if (NULL == resp)
+  {
+    free (json_str);
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  TALER_MHD_add_global_headers (resp);
+  GNUNET_break (MHD_YES ==
+                MHD_add_response_header (resp,
+                                         MHD_HTTP_HEADER_CONTENT_TYPE,
+                                         "application/json"));
+  if (MHD_YES == comp)
+  {
+    /* Need to indicate to client that body is compressed */
+    if (MHD_NO ==
+        MHD_add_response_header (resp,
+                                 MHD_HTTP_HEADER_CONTENT_ENCODING,
+                                 "deflate"))
+    {
+      GNUNET_break (0);
+      MHD_destroy_response (resp);
+      return MHD_NO;
+    }
+  }
+  ret = MHD_queue_response (connection,
+                            response_code,
+                            resp);
+  MHD_destroy_response (resp);
+  return ret;
+}
+
+
+/**
+ * Function to call to handle the request by building a JSON
+ * reply from a format string and varargs.
+ *
+ * @param connection the MHD connection to handle
+ * @param response_code HTTP response code to use
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json_pack (struct MHD_Connection *connection,
+                           unsigned int response_code,
+                           const char *fmt,
+                           ...)
+{
+  json_t *json;
+  va_list argp;
+  int ret;
+  json_error_t jerror;
+
+  va_start (argp, fmt);
+  json = json_vpack_ex (&jerror, 0, fmt, argp);
+  va_end (argp);
+  if (NULL == json)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to pack JSON with format `%s': %s\n",
+                fmt,
+                jerror.text);
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  ret = TALER_MHD_reply_json (connection,
+                              json,
+                              response_code);
+  json_decref (json);
+  return ret;
+}
+
+
+/**
+ * Make JSON response object.
+ *
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD response object
+ */
+struct MHD_Response *
+TALER_MHD_make_json_pack (const char *fmt,
+                          ...)
+{
+  json_t *json;
+  va_list argp;
+  struct MHD_Response *ret;
+  json_error_t jerror;
+
+  va_start (argp, fmt);
+  json = json_vpack_ex (&jerror,
+                        0,
+                        fmt,
+                        argp);
+  va_end (argp);
+  if (NULL == json)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to pack JSON with format `%s': %s\n",
+                fmt,
+                jerror.text);
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  ret = TALER_MHD_make_json (json);
+  json_decref (json);
+  return ret;
+}
+
+
+/**
+ * Create a response indicating an internal error.
+ *
+ * @param ec error code to return
+ * @param hint hint about the internal error's nature
+ * @return a MHD response object
+ */
+struct MHD_Response *
+TALER_MHD_make_error (enum TALER_ErrorCode ec,
+                      const char *hint)
+{
+  return TALER_MHD_make_json_pack ("{s:I, s:s}",
+                                   "code", (json_int_t) ec,
+                                   "hint", hint);
+}
+
+
+/**
+ * Send a response indicating an error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param http_status HTTP status code to use
+ * @param hint human readable hint about the error
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_with_error (struct MHD_Connection *connection,
+                            unsigned int http_status,
+                            enum TALER_ErrorCode ec,
+                            const char *hint)
+{
+  return TALER_MHD_reply_json_pack (connection,
+                                    http_status,
+                                    "{s:I, s:s}",
+                                    "code", (json_int_t) ec,
+                                    "hint", hint);
+}
+
+
+/**
+ * Send a response indicating that the request was too big.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_request_too_large (struct MHD_Connection *connection)
+{
+  struct MHD_Response *resp;
+  int ret;
+
+  resp = MHD_create_response_from_buffer (0,
+                                          NULL,
+                                          MHD_RESPMEM_PERSISTENT);
+  if (NULL == resp)
+    return MHD_NO;
+  TALER_MHD_add_global_headers (resp);
+  ret = MHD_queue_response (connection,
+                            MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
+                            resp);
+  MHD_destroy_response (resp);
+  return ret;
+}
+
+
+/**
+ * Function to call to handle the request by sending
+ * back a redirect to the AGPL source code.
+ *
+ * @param connection the MHD connection to handle
+ * @param url where to redirect for the sources
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_agpl (struct MHD_Connection *connection,
+                      const char *url)
+{
+  const char *agpl =
+    "This server is licensed under the Affero GPL. You will now be redirected to the source code.";
+  struct MHD_Response *response;
+  int ret;
+
+  response = MHD_create_response_from_buffer (strlen (agpl),
+                                              (void *) agpl,
+                                              MHD_RESPMEM_PERSISTENT);
+  if (NULL == response)
+  {
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  TALER_MHD_add_global_headers (response);
+  GNUNET_break (MHD_YES ==
+                MHD_add_response_header (response,
+                                         MHD_HTTP_HEADER_CONTENT_TYPE,
+                                         "text/plain"));
+  if (MHD_NO ==
+      MHD_add_response_header (response,
+                               MHD_HTTP_HEADER_LOCATION,
+                               url))
+  {
+    GNUNET_break (0);
+    MHD_destroy_response (response);
+    return MHD_NO;
+  }
+  ret = MHD_queue_response (connection,
+                            MHD_HTTP_FOUND,
+                            response);
+  MHD_destroy_response (response);
+  return ret;
+}
+
+
+/**
+ * Function to call to handle the request by sending
+ * back static data.
+ *
+ * @param rh context of the handler
+ * @param connection the MHD connection to handle
+ * @param http_status status code to return
+ * @param mime_type content-type to use
+ * @param body response payload
+ * @param body_size number of bytes in @a body
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_static (struct MHD_Connection *connection,
+                        unsigned int http_status,
+                        const char *mime_type,
+                        const char *body,
+                        size_t body_size)
+{
+  struct MHD_Response *response;
+  int ret;
+
+  response = MHD_create_response_from_buffer (body_size,
+                                              (void *) body,
+                                              MHD_RESPMEM_PERSISTENT);
+  if (NULL == response)
+  {
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  TALER_MHD_add_global_headers (response);
+  if (NULL != mime_type)
+    GNUNET_break (MHD_YES ==
+                  MHD_add_response_header (response,
+                                           MHD_HTTP_HEADER_CONTENT_TYPE,
+                                           mime_type));
+  ret = MHD_queue_response (connection,
+                            http_status,
+                            response);
+  MHD_destroy_response (response);
+  return ret;
+}
+
+
+/* end of mhd_responses.c */
diff --git a/src/util/crypto.c b/src/util/crypto.c
index 077f049eb..cf351d3f2 100644
--- a/src/util/crypto.c
+++ b/src/util/crypto.c
@@ -191,32 +191,6 @@ TALER_link_recover_transfer_secret (const struct
 
 
 /**
- * Set the bits in the private EdDSA key so that they match
- * the specification.
- *
- * @param[in,out] pk private key to patch
- */
-static void
-patch_private_key (struct GNUNET_CRYPTO_EddsaPrivateKey *pk)
-{
-  uint8_t *p = (uint8_t *) pk;
-
-  /* Taken from like 170-172 of libgcrypt/cipher/ecc.c
-   * We note that libgcrypt stores the private key in the reverse order
-   * from many Ed25519 implementatons. */
-  p[0] &= 0x7f;  /* Clear bit 255. */
-  p[0] |= 0x40;  /* Set bit 254.   */
-  p[31] &= 0xf8; /* Clear bits 2..0 so that d mod 8 == 0  */
-
-  /* FIXME: Run GNUNET_CRYPTO_ecdhe_key_create several times and inspect
-   * the output to verify that the same bits are set and cleared.
-   * Is it worth also adding a test case that runs gcry_pk_testkey on
-   * this key after first parsing it into libgcrypt's s-expression mess
-   * ala decode_private_eddsa_key from gnunet/src/util/crypto_ecc.c?
-   * It'd run check_secret_key but not test_keys from libgcrypt/cipher/ecc.c */}
-
-
-/**
  * Setup information for a fresh coin.
  *
  * @param secret_seed seed to use for KDF to derive coin keys
@@ -240,7 +214,6 @@ TALER_planchet_setup_refresh (const struct TALER_TransferSecretP *secret_seed,
                                     "taler-coin-derivation",
                                     strlen ("taler-coin-derivation"),
                                     NULL, 0));
-  patch_private_key (&ps->coin_priv.eddsa_priv);
 }
 
 
@@ -255,7 +228,6 @@ TALER_planchet_setup_random (struct TALER_PlanchetSecretsP *ps)
   GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_STRONG,
                               ps,
                               sizeof (*ps));
-  patch_private_key (&ps->coin_priv.eddsa_priv);
 }