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diff --git a/packages/taler-util/src/types-taler-bank-conversion.ts b/packages/taler-util/src/types-taler-bank-conversion.ts
new file mode 100644
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+++ b/packages/taler-util/src/types-taler-bank-conversion.ts
@@ -0,0 +1,200 @@
+/*
+ This file is part of GNU Taler
+ (C) 2024 Taler Systems S.A.
+
+ GNU 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.
+
+ GNU 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 Affero General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+
+ SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+import { codecForAmountString } from "./amounts.js";
+import {
+  Codec,
+  buildCodecForObject,
+  codecForConstString,
+  codecForEither,
+  codecForString,
+} from "./codec.js";
+import {
+  AmountString,
+  CurrencySpecification,
+  DecimalNumber,
+  codecForCurrencySpecificiation,
+  codecForDecimalNumber,
+} from "./types-taler-common.js";
+
+export interface ConversionInfo {
+  // Exchange rate to buy regional currency from fiat
+  cashin_ratio: DecimalNumber;
+
+  // Exchange rate to sell regional currency for fiat
+  cashout_ratio: DecimalNumber;
+
+  // Fee to subtract after applying the cashin ratio.
+  cashin_fee: AmountString;
+
+  // Fee to subtract after applying the cashout ratio.
+  cashout_fee: AmountString;
+
+  // Minimum amount authorised for cashin, in fiat before conversion
+  cashin_min_amount: AmountString;
+
+  // Minimum amount authorised for cashout, in regional before conversion
+  cashout_min_amount: AmountString;
+
+  // Smallest possible regional amount, converted amount is rounded to this amount
+  cashin_tiny_amount: AmountString;
+
+  // Smallest possible fiat amount, converted amount is rounded to this amount
+  cashout_tiny_amount: AmountString;
+
+  // Rounding mode used during cashin conversion
+  cashin_rounding_mode: "zero" | "up" | "nearest";
+
+  // Rounding mode used during cashout conversion
+  cashout_rounding_mode: "zero" | "up" | "nearest";
+}
+
+export interface TalerConversionInfoConfig {
+  // libtool-style representation of the Bank protocol version, see
+  // https://www.gnu.org/software/libtool/manual/html_node/Versioning.html#Versioning
+  // The format is "current:revision:age".
+  version: string;
+
+  // Name of the API.
+  name: "taler-conversion-info";
+
+  // Currency used by this bank.
+  regional_currency: string;
+
+  // How the bank SPA should render this currency.
+  regional_currency_specification: CurrencySpecification;
+
+  // External currency used during conversion.
+  fiat_currency: string;
+
+  // How the bank SPA should render this currency.
+  fiat_currency_specification: CurrencySpecification;
+
+  // Extra conversion rate information.
+  // Only present if server opts in to report the static conversion rate.
+  conversion_rate: ConversionInfo;
+}
+
+export interface CashinConversionResponse {
+  // Amount that the user will get deducted from their fiat
+  // bank account, according to the 'amount_credit' value.
+  amount_debit: AmountString;
+  // Amount that the user will receive in their regional
+  // bank account, according to 'amount_debit'.
+  amount_credit: AmountString;
+}
+
+export interface CashoutConversionResponse {
+  // Amount that the user will get deducted from their regional
+  // bank account, according to the 'amount_credit' value.
+  amount_debit: AmountString;
+  // Amount that the user will receive in their fiat
+  // bank account, according to 'amount_debit'.
+  amount_credit: AmountString;
+}
+
+export type RoundingMode = "zero" | "up" | "nearest";
+
+export interface ConversionRate {
+  // Exchange rate to buy regional currency from fiat
+  cashin_ratio: DecimalNumber;
+
+  // Fee to subtract after applying the cashin ratio.
+  cashin_fee: AmountString;
+
+  // Minimum amount authorised for cashin, in fiat before conversion
+  cashin_min_amount: AmountString;
+
+  // Smallest possible regional amount, converted amount is rounded to this amount
+  cashin_tiny_amount: AmountString;
+
+  // Rounding mode used during cashin conversion
+  cashin_rounding_mode: RoundingMode;
+
+  // Exchange rate to sell regional currency for fiat
+  cashout_ratio: DecimalNumber;
+
+  // Fee to subtract after applying the cashout ratio.
+  cashout_fee: AmountString;
+
+  // Minimum amount authorised for cashout, in regional before conversion
+  cashout_min_amount: AmountString;
+
+  // Smallest possible fiat amount, converted amount is rounded to this amount
+  cashout_tiny_amount: AmountString;
+
+  // Rounding mode used during cashout conversion
+  cashout_rounding_mode: RoundingMode;
+}
+
+export const codecForCashoutConversionResponse =
+  (): Codec<CashoutConversionResponse> =>
+    buildCodecForObject<CashoutConversionResponse>()
+      .property("amount_credit", codecForAmountString())
+      .property("amount_debit", codecForAmountString())
+      .build("TalerCorebankApi.CashoutConversionResponse");
+
+export const codecForCashinConversionResponse =
+  (): Codec<CashinConversionResponse> =>
+    buildCodecForObject<CashinConversionResponse>()
+      .property("amount_credit", codecForAmountString())
+      .property("amount_debit", codecForAmountString())
+      .build("TalerCorebankApi.CashinConversionResponse");
+
+export const codecForConversionInfo = (): Codec<ConversionInfo> =>
+  buildCodecForObject<ConversionInfo>()
+    .property("cashin_fee", codecForAmountString())
+    .property("cashin_min_amount", codecForAmountString())
+    .property("cashin_ratio", codecForDecimalNumber())
+    .property(
+      "cashin_rounding_mode",
+      codecForEither(
+        codecForConstString("zero"),
+        codecForConstString("up"),
+        codecForConstString("nearest"),
+      ),
+    )
+    .property("cashin_tiny_amount", codecForAmountString())
+    .property("cashout_fee", codecForAmountString())
+    .property("cashout_min_amount", codecForAmountString())
+    .property("cashout_ratio", codecForDecimalNumber())
+    .property(
+      "cashout_rounding_mode",
+      codecForEither(
+        codecForConstString("zero"),
+        codecForConstString("up"),
+        codecForConstString("nearest"),
+      ),
+    )
+    .property("cashout_tiny_amount", codecForAmountString())
+    .build("ConversionBankConfig.ConversionInfo");
+
+export const codecForConversionBankConfig = (): Codec<TalerConversionInfoConfig> =>
+  buildCodecForObject<TalerConversionInfoConfig>()
+    .property("name", codecForConstString("taler-conversion-info"))
+    .property("version", codecForString())
+    .property("regional_currency", codecForString())
+    .property(
+      "regional_currency_specification",
+      codecForCurrencySpecificiation(),
+    )
+    .property("fiat_currency", codecForString())
+    .property("fiat_currency_specification", codecForCurrencySpecificiation())
+
+    .property("conversion_rate", codecForConversionInfo())
+    .build("ConversionBankConfig.IntegrationConfig");