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OpenAPI specs

You can now download the OpenAPI specs of the Maesn Unified API. Use them to generate a client in your language, import the API into tools like Postman, or give an AI agent a full description of the API. The specs always match the live API. More details here

Partial errors

Some requests make more than one call to the target system. If the main object is created but a later step fails, for example the file upload, the API now still returns a success response. The failed step is listed in meta.partialErrors, so you keep the created object and can retry only the step that failed. This is supported for POST /bookingProposals in Microsoft Business Central, Lexware Office, Procountor, Snelstart and Xero. More details here

Booking proposal attachments

You can now add a file to an existing booking proposal with POST /bookingProposals/:id/attachments. This is available for Microsoft Business Central, Moneybird, Procountor, Snelstart and Xero.

New endpoints:

AbaConnect

Holded

Lexware Office

Microsoft Business Central

Improvements:

  • Idempotency keys are now supported for POST /journalEntries.
  • Booking proposals for Lexware Office now support credit notes as well as invoices and bills.
  • The async task status is now SUCCESS, FAILED or PARTIAL_SUCCESS for AbaConnect tasks. PARTIAL_SUCCESS means the object was created but couldn’t be read back.
  • Holded now uses Holded’s new API keys with scoped permissions. The integration page lists the scopes each endpoint needs.

Idempotency keys Beta

You can now send an idempotency-key header with POST requests, so that you can safely retry a request without creating duplicates in the target system. This is supported for POST /bookingProposals, POST /bookingProposals/async and POST /journalEntries/bulk. More details here

Custom texts on authentication pages

You can now set your own title, free text and button labels on the authentication pages, in several languages. Pass a locale when you request the authentication URL to choose the language. More details here

New endpoints:

DATEV Rechnungswesen

Fortnox

Lexware Office

Snelstart

Tripletex

Improvements:

New integration:

  • Tripletex is now available via the Maesn Unified API

New endpoints:

Abacus

Dinero

Fortnox

Lexware Office

Procountor

Tripletex

Visma e-conomic

Improvements:

  • Draft (unbooked) journal entries are now supported for Dinero and Visma e-conomic via the isProvisional flag when creating or updating journal entries.

New asynchronous endpoints

We released new asynchronous versions of two endpoints, so that you can post your data to DATEV without concerns about refresh token race conditions or rate-limits

Signed authentication callbacks

We implemented signed authentication callbacks, so that you can be certain that your callbacks originate from your platform and not a malicious actor. More details here

New endpoints:

Exact Online

Buchhaltungsbutler

sevdesk

Last modified on November 3, 2026