taler-docs

api-bank-wire.rst (24471B)

---

 ..
   This file is part of GNU TALER.
   Copyright (C) 2019-2025, 2026 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 2.1, 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/>
 
 .. _taler-wire-gateway-http-api:
 
 ===========================
 Taler Wire Gateway HTTP API
 ===========================
 
 This section describes the API offered by the Taler wire adapters. The API is
 used by the exchange to trigger transactions and query incoming transactions, as
 well as by the auditor to query incoming and outgoing transactions.
 
 This API is currently implemented by the Taler Demo Bank, as well as by
 LibEuFin.
 
 .. http:get:: /config
 
   Return the protocol version and configuration information about the bank.
   This specification corresponds to ``current`` protocol being version **5**.
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     The adapter responds with a `WireConfig` object. This request should
     virtually always be successful.
 
   **Details:**
 
   .. ts:def:: WireConfig
 
     interface WireConfig {
       // Name of the API.
       name: "taler-wire-gateway";
 
       // 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;
 
       // Currency used by this gateway.
       currency: string;
 
       // URN of the implementation (needed to interpret 'revision' in version).
       // @since v0, may become mandatory in the future.
       implementation?: string;
 
       // Whether implementation support account existence check
       support_account_check: boolean;
     }
 
 --------------
 Authentication
 --------------
 
 The bank library authenticates requests to the wire gateway via
 `HTTP basic auth <https://tools.ietf.org/html/rfc7617>`_.
 
 -------------------
 Making Transactions
 -------------------
 
 .. http:post:: /transfer
 
   Initiate a new wire transfer from the exchange's bank account, typically to a
   merchant.
 
   The exchange's bank account is not included in the request, but instead
   derived from the username in the ``Authorization`` header and/or the request
   base URL.
 
   To make the API idempotent, the client must include a nonce. Requests with
   the same nonce are rejected unless the request is the same.
 
   **Request:**
 
   .. ts:def:: TransferRequest
 
     interface TransferRequest {
       // Nonce to make the request idempotent.  Requests with the same
       // ``request_uid`` that differs in any of the other fields
       // are rejected.
       request_uid: HashCode;
 
       // Amount to transfer.
       amount: Amount;
 
       // Base URL of the exchange.  Shall be included by the bank gateway
       // in the appropriate section of the wire transfer details.
       exchange_base_url: string;
       
       // Optional additional metadata to be stored in the transaction.
       // Must match [a-zA-Z0-9-.:]{1, 40}
       // @since **v5**
       metadata?: string;
 
       // Wire transfer identifier chosen by the exchange,
       // used by the merchant to identify the Taler order(s)
       // associated with this wire transfer.
       wtid: ShortHashCode;
 
       // The recipient's account identifier as a full payto URI.
       credit_account: string;
     }
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     The request has been correctly handled, so the funds have been transferred to
     the recipient's account.  The body is a `TransferResponse`.
   :http:statuscode:`400 Bad request`:
     Request malformed. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     The endpoint is wrong or the user name is unknown. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`409 Conflict`:
     * ``TALER_EC_BANK_TRANSFER_REQUEST_UID_REUSED``: an operation with the same ``request_uid`` but different details has been submitted before.
     * ``TALER_EC_BANK_TRANSFER_WTID_REUSED``: an operation with the same ``wtid`` but a different ``request_uid`` has been submitted before.
 
   **Details:**
 
   .. ts:def:: TransferResponse
 
     interface TransferResponse {
       // Timestamp that indicates when the wire transfer will be executed.
       // In cases where the wire transfer gateway is unable to know when
       // the wire transfer will be executed, the time at which the request
       // has been received and stored will be returned.
       // The purpose of this field is for debugging (humans trying to find
       // the transaction) as well as for taxation (determining which
       // time period a transaction belongs to).
       timestamp: Timestamp;
 
       // Opaque ID of the wire transfer initiation performed by the bank.
       // It is different from the /history endpoints row_id.
       row_id: SafeUint64;
     }
 
 .. http:get:: /transfers
 
   Return a list of transfers initiated from the exchange.
 
   The bank account of the exchange is determined via the base URL and/or the
   user name in the ``Authorization`` header. The transfer history
   might come from a "virtual" account, where multiple real bank accounts are
   merged into one history.
 
   Since protocol **v3**.
 
   **Request:**
 
   :query limit: *Optional.*
     At most return the given number of results. Negative for descending by
     ``row_id``, positive for ascending by ``row_id``. Defaults to ``-20``.
   :query offset: *Optional.*
     Starting ``row_id`` for :ref:`pagination <row-id-pagination>`.
   :query status: *Optional*.
     Filters by status.
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     JSON object of type `TransferList`.
   :http:statuscode:`204 No content`:
     There are no transfers to report (under the given filter).
   :http:statuscode:`400 Bad request`:
     Request malformed.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     The endpoint is wrong or the user name is unknown.
 
   **Details:**
 
   .. ts:def:: TransferList
 
     interface TransferList {
       // Array of initiated transfers.
       transfers: TransferListStatus[];
 
       // Full payto:// URI to identify the sender of funds.
       // This must be one of the exchange's bank accounts.
       // Credit account is shared by all incoming transactions
       // as per the nature of the request.
       debit_account: string;
     }
 
   .. ts:def:: TransferListStatus
 
     interface TransferListStatus {
       // Opaque ID of the wire transfer initiation performed by the bank.
       // It is different from the /history endpoints row_id.
       row_id: SafeUint64;
 
       // Current status of the transfer
       // pending: the transfer is in progress
       // transient_failure: the transfer has failed but may succeed later
       // permanent_failure: the transfer has failed permanently and will never appear in the outgoing history
       // success: the transfer has succeeded  and appears in the outgoing history
       status: "pending" | "transient_failure" | "permanent_failure" | "success";
 
       // Amount to transfer.
       amount: Amount;
 
       // The recipient's account identifier as a full payto:// URI.
       credit_account: string;
 
       // Timestamp that indicates when the wire transfer was executed.
       // In cases where the wire transfer gateway is unable to know when
       // the wire transfer will be executed, the time at which the request
       // has been received and stored will be returned.
       // The purpose of this field is for debugging (humans trying to find
       // the transaction) as well as for taxation (determining which
       // time period a transaction belongs to).
       timestamp: Timestamp;
     }
 
 
 .. http:get:: /transfers/$ROW_ID
 
   Return the status of a transfer initiated from the exchange, identified by the ``ROW_ID``.
 
   Since protocol **v3**.
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     The transfer is known, and details are given in the `TransferStatus` response body.
   :http:statuscode:`400 Bad request`:
     Request malformed.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     The transfer was not found.
 
   **Details:**
 
   .. ts:def:: TransferStatus
 
     interface TransferStatus {
       // Current status of the transfer
       // pending: the transfer is in progress
       // transient_failure: the transfer has failed but may succeed later
       // permanent_failure: the transfer has failed permanently and will never appear in the outgoing history
       // success: the transfer has succeeded  and appears in the outgoing history
       status: "pending" | "transient_failure" | "permanent_failure" | "success";
 
       // Optional unstructured messages about the transfer's status. Can be used to document the reasons for failure or the state of progress.
       status_msg?: string;
 
       // Amount to transfer.
       amount: Amount;
 
       // Base URL of the exchange.  Shall be included by the bank gateway
       // in the appropriate section of the wire transfer details.
       exchange_base_url: string;
       
       // Optional additional metadata to be stored in the transaction.
       // @since **v5**
       metadata?: string;
 
       // Wire transfer identifier chosen by the exchange,
       // used by the merchant to identify the Taler order(s)
       // associated with this wire transfer.
       wtid: ShortHashCode;
 
       // The recipient's account identifier as a full payto URI.
       credit_account: string;
 
       // Timestamp that indicates when the wire transfer was executed.
       // In cases where the wire transfer gateway is unable to know when
       // the wire transfer will be executed, the time at which the request
       // has been received and stored will be returned.
       // The purpose of this field is for debugging (humans trying to find
       // the transaction) as well as for taxation (determining which
       // time period a transaction belongs to).
       timestamp: Timestamp;
     }
 
 --------------------------------
 Querying the transaction history
 --------------------------------
 
 The exchange's bank account is derived from the username in the
 ``Authorization`` header and/or the request's base URL. In fact, the
 transaction history may come from a "virtual" account, where several real bank
 accounts are merged into a single history.
 
 .. http:get:: /history/incoming
 
   Return a list of transactions made from or to the exchange.
 
   Incoming transactions must contain a valid reserve public key.  If a bank
   transaction does not conform to the right syntax, the wire gateway must not
   report it to the exchange, and send funds back to the sender if possible.
 
   **Request:**
 
   :query limit: *Optional.*
     At most return the given number of results. Negative for descending by ``row_id``, positive for ascending by ``row_id``. Defaults to ``-20``. Since protocol **v2**.
   :query offset: *Optional.*
     Starting ``row_id`` for :ref:`pagination <row-id-pagination>`. Since protocol **v2**.
   :query timeout_ms: *Optional.*
     Timeout in milliseconds, for :ref:`long-polling <long-polling>`, to wait for at least one element to be shown. Only useful if *limit* is positive. Since protocol **v2**.
   :query delta: *Optional.*
     Deprecated in protocol **v2**. Use *limit* instead.
   :query start: *Optional.*
     Deprecated in protocol **v2**. Use *offset* instead.
   :query long_poll_ms: *Optional.*
     Deprecated in protocol **v2**. Use *timeout_ms* instead.
 
   **Response:**
 
   :http:statuscode:`200 OK`:
      JSON object of type `IncomingHistory`.
   :http:statuscode:`204 No content`:
     There are not transactions to report (under the given filter).
   :http:statuscode:`400 Bad request`:
      Request malformed. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`401 Unauthorized`:
      Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
      The endpoint is wrong or the user name is unknown. The bank replies with an `ErrorDetail` object.
 
   **Details:**
 
   .. ts:def:: IncomingHistory
 
     interface IncomingHistory {
       // Array of incoming transactions.
       incoming_transactions: IncomingBankTransaction[];
 
       // Full payto URI to identify the receiver of funds.
       // This must be one of the exchange's bank accounts.
       // Credit account is shared by all incoming transactions
       // as per the nature of the request.
       credit_account: string;
     }
 
   .. ts:def:: IncomingBankTransaction
 
     // Union discriminated by the "type" field.
     type IncomingBankTransaction =
     | IncomingKycAuthTransaction
     | IncomingReserveTransaction
     | IncomingWadTransaction;
 
   .. ts:def:: IncomingKycAuthTransaction
 
     // Since protocol **v1**.
     interface IncomingKycAuthTransaction {
       type: "KYCAUTH";
 
       // Opaque identifier of the returned record.
       row_id: SafeUint64;
 
       // Date of the transaction.
       date: Timestamp;
 
       // Amount received before credit_fee.
       amount: Amount;
 
       // Fee paid by the creditor.
       // If not null, creditor actually received amount - credit_fee
       // @since **v3**
       credit_fee?: Amount;
 
       // Full payto URI to identify the sender of funds.
       debit_account: string;
 
       // The account public key extracted from the transaction details.
       account_pub: EddsaPublicKey;
 
       // The authorization public key used for mapping
       // @since **v5**
       authorization_pub?: EddsaPublicKey;
 
       // Signature of the account public key using the authorization private key
       // @since **v5**
       authorization_sig?: EddsaSignature;
     }
 
   .. ts:def:: IncomingReserveTransaction
 
     interface IncomingReserveTransaction {
       type: "RESERVE";
 
       // Opaque identifier of the returned record.
       row_id: SafeUint64;
 
       // Date of the transaction.
       date: Timestamp;
 
       // Amount received before credit_fee.
       amount: Amount;
 
       // Fee payed by the creditor.
       // If not null, creditor actually received amount - 
       // @since **v3**
       credit_fee?: Amount;
 
       // Full payto URI to identify the sender of funds.
       debit_account: string;
 
       // The reserve public key extracted from the transaction details.
       reserve_pub: EddsaPublicKey;
 
       // The authorization public key used for mapping
       // @since **v5**
       authorization_pub?: EddsaPublicKey;
 
       // Signature of the reserve public key using the authorization private key
       // @since **v5**
       authorization_sig?: EddsaSignature;
     }
 
   .. ts:def:: IncomingWadTransaction
 
     interface IncomingWadTransaction {
       type: "WAD";
 
       // Opaque identifier of the returned record.
       row_id: SafeUint64;
 
       // Date of the transaction.
       date: Timestamp;
 
       // Amount received before credit_fee.
       amount: Amount;
 
       // Fee payed by the creditor.
       // If not null, creditor actually received amount - credit_fee
       // @since **v3**
       credit_fee?: Amount;
 
       // Full payto URI to identify the sender of funds.
       debit_account: string;
 
       // Base URL of the exchange that originated the wad.
       origin_exchange_url: string;
 
       // The reserve public key extracted from the transaction details.
       wad_id: WadId;
     }
 
 
 .. http:get:: /history/outgoing
 
   Return a list of transactions made by the exchange, typically to a merchant.
 
   **Request:**
 
   :query limit: *Optional.*
     At most return the given number of results. Negative for descending by ``row_id``, positive for ascending by ``row_id``. Defaults to ``-20``. Since protocol **v2**.
   :query offset: *Optional.*
     Starting ``row_id`` for :ref:`pagination <row-id-pagination>`. Since protocol **v2**.
   :query timeout_ms: *Optional.*
     Timeout in milliseconds, for :ref:`long-polling <long-polling>`, to wait for at least one element to be shown. Only useful if *limit* is positive. Since protocol **v2**.
   :query delta: *Optional.*
     Deprecated in protocol **v2**. Use *limit* instead.
   :query start: *Optional.*
     Deprecated in protocol **v2**. Use *offset* instead.
   :query long_poll_ms: *Optional.*
     Deprecated in protocol **v2**. Use *timeout_ms* instead.
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     JSON object of type `OutgoingHistory`.
   :http:statuscode:`204 No content`:
     There are not transactions to report (under the given filter).
   :http:statuscode:`400 Bad request`:
     Request malformed. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     The endpoint is wrong or the user name is unknown. The bank replies with an `ErrorDetail` object.
 
   **Details:**
 
   .. ts:def:: OutgoingHistory
 
     interface OutgoingHistory {
       // Array of outgoing transactions.
       outgoing_transactions: OutgoingBankTransaction[];
 
       // Full payto URI to identify the sender of funds.
       // This must be one of the exchange's bank accounts.
       // Credit account is shared by all incoming transactions
       // as per the nature of the request.
       debit_account: string;
     }
 
   .. ts:def:: OutgoingBankTransaction
 
     interface OutgoingBankTransaction {
       // Opaque identifier of the returned record.
       row_id: SafeUint64;
 
       // Date of the transaction.
       date: Timestamp;
 
       // Amount transferred.
       amount: Amount;
 
       // Fee paid by the debtor.
       // If not null, debtor actually paid amount + debit_fee
       // @since **v3**
       debit_fee?: Amount;
 
       // Full payto URI to identify the receiver of funds.
       credit_account: string;
 
       // The wire transfer ID in the outgoing transaction.
       wtid: ShortHashCode;
 
       // Base URL of the exchange.
       exchange_base_url: string;
       
       // Optional additional metadata.
       // @since **v5**
       metadata?: string;
     }
 
 
 -----------------
 Wire Account APIs
 -----------------
 
 .. http:get:: /account/check
 
   Check account existence.
 
   Since protocol **v4**.
 
   **Request:**
 
   :query account:
     Payto URI of the account.
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     JSON object of type `AccountInfo`.
   :http:statuscode:`400 Bad request`:
     Request malformed. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     * ``TALER_EC_BANK_UNKNOWN_ACCOUNT``: unknown account.
   :http:statuscode:`501 Not Implemented`:
     This server does not support account check.
 
   **Details:**
 
   .. ts:def:: AccountInfo
 
     interface AccountInfo {
     }
 
 -----------------------
 Wire Transfer Test APIs
 -----------------------
 
 Endpoints in this section are only used for integration tests and never
 exposed by bank gateways in production.
 
 .. _twg-admin-add-incoming:
 
 .. http:post:: /admin/add-incoming
 
   Simulate a transfer from a customer to the exchange.  This API is *not*
   idempotent since it's only used in testing.
 
   **Request:**
 
   .. ts:def:: AddIncomingRequest
 
     interface AddIncomingRequest {
       // Amount to transfer.
       amount: Amount;
 
       // Reserve public key that is included in the wire transfer details
       // to identify the reserve that is being topped up.
       reserve_pub: EddsaPublicKey;
 
       // Account (as full payto URI) that makes the wire transfer to the exchange.
       // Usually this account must be created by the test harness before this
       // API is used. An exception is the "fakebank", where any debit account
       // can be specified, as it is automatically created.
       debit_account: string;
     }
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     The request has been correctly handled, so the funds have been transferred to
     the recipient's account.  The body is a `AddIncomingResponse`.
   :http:statuscode:`400 Bad request`:
     The request is malformed. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     The endpoint is wrong or the user name is unknown. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`409 Conflict`:
     The 'reserve_pub' argument was used previously in another transfer, and the specification mandates that reserve public keys must not be reused.
 
   **Details:**
 
   .. ts:def:: AddIncomingResponse
 
     interface AddIncomingResponse {
       // Timestamp that indicates when the wire transfer will be executed.
       // In cases where the wire transfer gateway is unable to know when
       // the wire transfer will be executed, the time at which the request
       // has been received and stored will be returned.
       // The purpose of this field is for debugging (humans trying to find
       // the transaction) as well as for taxation (determining which
       // time period a transaction belongs to).
       timestamp: Timestamp;
 
       // Opaque ID of the wire transfer initiation performed by the bank.
       // It is different from the /history endpoints row_id.
       row_id: SafeUint64;
     }
 
 
 
 .. _twg-admin-add-kycauth:
 
 .. http:post:: /admin/add-kycauth
 
   Simulate a transfer from a customer to the exchange.  This API is *not*
   idempotent since it's only used in testing.
 
   **Request:**
 
   .. ts:def:: AddKycauthRequest
 
     interface AddKycauthRequest {
       // Amount to transfer.
       amount: Amount;
 
       // Account public key that is included in the wire transfer details
       // to associate this key with the originating bank account.
       account_pub: EddsaPublicKey;
 
       // Account (as full payto URI) that makes the wire transfer to the exchange.
       // Usually this account must be created by the test harness before this
       // API is used. An exception is the "fakebank", where any debit account
       // can be specified, as it is automatically created.
       debit_account: string;
     }
 
   **Response:**
 
   :http:statuscode:`200 OK`:
     The request has been correctly handled, so the funds have been transferred to
     the recipient's account.  The body is a `AddKycauthResponse`.
   :http:statuscode:`400 Bad request`:
     The request is malformed. The bank replies with an `ErrorDetail` object.
   :http:statuscode:`401 Unauthorized`:
     Authentication failed, likely the credentials are wrong.
   :http:statuscode:`404 Not found`:
     The endpoint is wrong or the user name is unknown. The bank replies with an `ErrorDetail` object.
 
   **Details:**
 
   .. ts:def:: AddKycauthResponse
 
     interface AddKycauthResponse {
       // Timestamp that indicates when the wire transfer will be executed.
       // In cases where the wire transfer gateway is unable to know when
       // the wire transfer will be executed, the time at which the request
       // has been received and stored will be returned.
       // The purpose of this field is for debugging (humans trying to find
       // the transaction) as well as for taxation (determining which
       // time period a transaction belongs to).
       timestamp: Timestamp;
 
       // Opaque ID of the wire transfer initiation performed by the bank.
       // It is different from the /history endpoints row_id.
       row_id: SafeUint64;
     }
 
 
 Security Considerations
 =======================
 
 For implementors:
 
 * The withdrawal operation ID must contain enough entropy to be unguessable.
 
 Design:
 
 * The user must complete the 2FA step of the withdrawal in the context of their banking
   app or online banking Website.
   We explicitly reject any design where the user would have to enter a confirmation code
   they get from their bank in the context of the wallet, as this would teach and normalize
   bad security habits.