..
  This file is part of GNU TALER.
  Copyright (C) 2014-2023 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/>

  @author Florian Dold
  @author Benedikt Muller
  @author Sree Harsha Totakura
  @author Marcello Stanisci
  @author Christian Grothoff

---------------------------
Core Protocol Specification
---------------------------

This chapter describes the APIs used in the GNU Taler project.  It includes
both APIs that are pre-existing as well as APIs specific to the project.

These *protocol specification* defines the HTTP-based, predominantly RESTful
interfaces between the core components of Taler.


.. toctree::
  :maxdepth: 2

  api-common
  api-error
  api-exchange
  api-merchant
  api-auditor
  api-sync
  api-taldir
  api-mailbox
  api-wire
  api-bank-merchant
  api-bank-integration
  api-bank-access

.. toctree::
  :hidden:

========
Overview
========

  * Taler Exchange Public API


    **Summary**: Public API for the payment service provider component of GNU Taler.

    **Providers**: GNU Taler Exchange

    **Consumers**: Wallet, Merchant
    
    :doc:`Docs <api-exchange>`


  * Taler Exchange Management API

    **Summary**: Management API for the payment service provider component of GNU Taler.

    **Providers**: GNU Taler Exchange

    **Consumers**: Exchange tooling (``taler-exchange-offline``), Auditor

    :doc:`Docs <api-exchange>`


  * Taler Merchant Backend Public API

    **Summary**: Allows communication between merchants and users' wallets.

    **Providers**: GNU Taler Merchant backend

    **Consumers**: Wallet

    :doc:`Docs <api-merchant>`

  * Taler Merchant Backend Private API

    **Summary**: Allows the merchant to manage Taler-based payments and related functionality.

    **Providers**: GNU Taler Merchant backend

    **Consumers**: Merchant's shop Website backend, Merchant PoS app, Merchant Backoffice UI

    :doc:`Docs <api-merchant>`

  * Taler Wallet Core API

    **Summary**: API to access functionality of the Taler Wallet service running locally on user's devices.

    **Providers**: wallet-core

    **Consumers**: UIs for the GNU Taler wallet

  * Taler Bank Integration API

    **Summary**: Offered by banks to provide the wallet/user with more information about ongoing withdrawals of Taler digital cash.

    **Providers**: Taler fakebank, LibEuFin demobank, Banks (that provide extra Taler support)

    **Consumers**: Taler Wallet

    :doc:`Docs <api-bank-integration>`

  * Taler Bank Access API

    **Summary**: Protocol to manage access to a bank account by the owner of the account. Allows access to account balance, transaction list, payment initiation.

    **Providers**: LibEuFin demobank, Taler Fakebank (partial)

    **Consumers**: Cashier App, demobank-ui

    :doc:`Docs <api-bank-access>`


  * Taler Bank Circuits API

    **Summary**: Allows management of bank user accounts in a regional currency bank deployment.

    **Providers**: LibEuFin Sandbox demobank

    **Consumers**: demobank-ui

  * Taler Wire Gateway API

    **Summary**: Allows the Taler Exchange to query incoming transactions and initiate payments with a protocol that abstracts away details of the underlying banking system.

    **Providers**: Taler fakebank, LibEuFin Nexus, Depoloymerization wire gateway

    **Consumers**: GNU Taler Exchange, Wire Auditor

    :doc:`Docs <api-wire>`

  * Taler Sync API

    **Summary**: Encrypted Data blob storage and retrieval API with payments for storage handled by GNU Taler payments.

    **Providers**: GNU Taler Sync service

    **Consumers**: Taler Wallet

    :doc:`Docs <api-sync>`

  * Taler Auditor API

    **Summary**: Reporting of certain transactions or potential problems directly to the auditor.

    **Providers**: GNU Taler Auditor service

    **Consumers**: GNU Taler Merchant, eventually Taler Wallet

    :doc:`Docs <api-auditor>`

  * Taldir API

    **Summary**: Looking up of Taler mailboxes associated with particular Internet service addresses.

    **Providers**: GNU TalDir service

    **Consumers**: GNU Taler Wallet

    :doc:`Docs <api-taldir>`

  * Taler Mailbox API

    **Summary**: Tansmission of encrypted payment messages between Taler wallets.

    **Providers**: GNU Taler Mailbox service

    **Consumers**: GNU Taler Wallet

    :doc:`Docs <api-mailbox>`

  * Anastasis Provider Public API

    **Summary**: Backup for secret splitting backup and recovery with GNU Anastasis providers.

    **Providers**: GNU Anastasis providers

    **Consumers**: Anastasis core client implementations (C implementation, TypeScript implementation)

  * Anastasis Reducer API

    **Summary**:  API used to step through the backup and recovery process of GNU Anastasis.

    **Providers**: Anastasis core client implementations (C implementation, TypeScript implementation)

    **Consumers**: Anastasis UIs (CLI, GTK, anastasis-webui)

  * LibEuFin Nexus API

    **Summary**: API used to configure and access LibEuFin nexus, a generic server that supports multiple protocols to access a bank account.

    **Providers**: LibEuFin Nexus service

    **Consumers**: ``libeufin-cli``, (future) LibEuFin Web UI

  * LibEuFin Sandbox API

    **Summary** API used to configure the LibEuFin sandbox, a simulator for various protocols related to core banking that would typically offered by banks.

    **Providers**: LibEuFin Sandbox service

    **Consumers**: ``libeufin-cli``, (future) LibEuFin Web UI

  * EBICS

    **Summary**: Allows businesses/banks/consumers to exchange data with a bank's core banking system.

    **Consumers**: LibEuFin Nexus

    **Providers**: LibEuFin Sandbox, Banks