# Diebold Nixdorf > Diebold Nixdorf builds connected-commerce technology for banks and retailers: ATMs and self-service > terminals, retail point-of-sale hardware, the Vynamic software portfolio, and the managed services > around them. Its API surface is the Vynamic banking stack — Transaction Middleware and the interfaces > that connect self-service and digital channels to a core banking system. Generated: 2026-09-06 by API Evangelist (apievangelist.com) from the eight OpenAPI definitions Diebold Nixdorf publishes through its SwaggerHub organization. This file is written by a third party, not by Diebold Nixdorf. Diebold Nixdorf serves no llms.txt of its own (https://www.dieboldnixdorf.com/llms.txt returned HTTP 404 on 2026-09-06). ## Read this first Every one of these APIs is CUSTOMER-DEPLOYED. The servers[] block in each specification names `localhost:8080` because Vynamic Transaction Middleware runs inside the financial institution's own environment. There is no shared Diebold Nixdorf endpoint an agent can call, no public signup, no sandbox, no published price and no published rate limit. Access follows a customer or partner relationship. The base URL is the bank's, not the vendor's. ## APIs - [DN Open Backend API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/dn-open_backend_api/4.3.0): Banking core integration — authentication, account information, consumer information, account processing. 62 paths, OpenAPI 3.0.1, version 4.3.0. Carries the two-phase authorize/finalize protocol used by withdrawal, deposit, check cashing and mixed-media payment. - [DN Online & Mobile API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/dn_online_mobile_api/3.2.1): Online and mobile banking channel into the Transaction Middleware, including a SEPA Instant push/pull payment surface. 35 paths, OpenAPI 3.0.3, version 3.2.1. - [DN Assist API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/dn-assist_api/1.0): Self-service assistance — terminal status, session and customer data, remote commands, teller hand-off. 23 paths, OpenAPI 3.0.1, version 1.0. - [DN Payment Initiation API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/dn_payment_initiation_api/1.9.11): Cardless and card-based payment initiation, confirm, cancel, refund and payment-device management. Uses the Berlin Group NextGenPSD2 PSU header set and OpenID Connect. 11 paths, version 1.9.11. - [DN TM Authorization API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/DN-TM-Authorization-API/1.8.1): Token issuance and key retrieval for the Transaction Middleware. 8 paths, version 1.8.1. - [DN Account BC API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/dn-account_api/1.0.0): Account balance management, transaction authorization and reversal, notifications. 5 paths. - [DN Secure Business Processing API](https://api.swaggerhub.com/apis/Diebold-Nixdorf/dn_pledge_api/3.1.0): Invokes a preconfigured business process flow in one request, authorized via an external OpenID provider. 2 paths, version 3.1.0, unchanged since 2022. - [TM Pre-Digitization API (Outbound)](https://api.swaggerhub.com/apis/Diebold-Nixdorf/tm-pre-digitization-api-outbound/1.0.0): Outbound calls to card issuers during card digitization — customer information, activation code delivery, digitization completion. 3 paths. ## Machine-readable artifacts in this repository - Specifications: `openapi/` (eight documents, plus the verbatim harvested JSON in `openapi/_original/`) - Authentication profile: `authentication/diebold-authentication.yml` - Runtime semantics, idempotency and reversibility: `conventions/diebold-conventions.yml` - Error catalog (162 numeric application codes): `errors/diebold-problem-types.yml` - Authorization decline codes: `errors/diebold-decline-codes.yml` - Standards signatures: `conformance/diebold-conformance.yml` - Versions and decay: `lifecycle/diebold-lifecycle.yml` - Entity graph: `data-model/diebold-data-model.yml` - Agent skills: `skills/_index.yml` - Discovery-document probe log: `well-known/diebold-well-known.yml` ## What an agent needs to know before calling anything here - Auth: HTTP Basic or Bearer on the banking surfaces; OpenID Connect on Payment Initiation (Microsoft Entra ID tenant) and on Secure Business Processing. Tokens come from `getToken`, `tm-authenticate` or `/token`. The Open Backend and Assist APIs also accept a JWE-encrypted bearer, keyed by `getRsaKey` / `getEcKey` / `pkiKey`. - Idempotency is PARTIAL. Two of 116 mutating operations state a replay key — `cancel` and `refund` on the Payment Initiation API, both keyed on `transactionId`. There is no `Idempotency-Key` header. The other 114 writes, including every money-moving Open Backend operation, document nothing. - Reversal paths exist and are well populated (`reversal`, `transferReversal`, `cancelAccountHold`, `reverseTransaction`, `cancel`, `refund`, `cancelPushPayment`, `cancelPullPayment`), but NO specification states a window inside which a reversal is accepted. Do not assume one. - Errors are vendor JSON, not RFC 9457. Read `responseCode` (OK | FAIL | RESUBMIT) and `extendedResponseCode` (40 business outcomes) as well as the HTTP status. - Pagination does not exist. Collection reads are bounded by date range. - No rate-limit headers, no 429, no status page, no deprecation policy. ## Not available - No public developer portal. `developer.dieboldnixdorf.com` is a dangling CNAME to a decommissioned Salesforce Experience Cloud site and does not resolve. - The Vynamic Retail Platform developer portal, `vrp-api.dieboldnixdorf.com`, is a SwaggerHub Portal behind a login; every path returns HTTP 302 to `portal.swaggerhub.com`. - No SDKs on npm, PyPI, Maven Central, NuGet, RubyGems, crates.io or Packagist. The GitHub organization `DieboldNixdorf` has zero public repositories. - No MCP server, no A2A agent card, no AsyncAPI, no WSDL, no gRPC contract. ## Company - [Diebold Nixdorf](https://www.dieboldnixdorf.com) - [Support](https://www.dieboldnixdorf.com/en-us/support) - [Global Security Portal](https://www.dieboldnixdorf.com/en-us/support/globalsecurityportal) - [Report a security concern](https://www.dieboldnixdorf.com/en-us/support/globalsecurityportal/contactsecurity) - [Terms of Use](https://www.dieboldnixdorf.com/en-us/terms-of-use) - [Global Privacy Notice](https://www.dieboldnixdorf.com/en-us/privacy-policy/global-privacy-notice)