Changelog

Product updates and announcements for the Maesn API

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September 2026

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

• GET /openItems/async

Fortnox

• GET /journalEntries
• GET /journalEntries/:id
• POST /journalEntries
• PUT /journalEntries

Lexware Office

• POST /offers

Snelstart

• GET /journals
• GET /openItems
• POST /payments

Tripletex

• GET /accounts
• GET /journalEntries
• GET /journalEntries/:id
• POST /journalEntries
• PATCH /journalEntries/:id

Improvements:

• Webhooks for offers are now available for Lexware Office.
• SKR07 is now supported as chart of accounts for DATEV, for example in GET /fiscalYears.
• GET /accounts for DATEV Rechnungswesen can now be filtered by isActive.
• POST /journalEntries/bulk for DATEV Rechnungswesen now accepts an additionalInformation field per journal entry.
• POST /files and POST /files/async for DATEV Rechnungswesen now accept a folderName field.
• Contacts now expose more fields, including vatId, bankAccounts, businessRegistrationNumber, parentId, birthDate and jobTitle. See GET /contacts for which fields each system supports.
• Customers and suppliers now support vatId for Lexware Office, and number and vatId for Exact Online.
• The async task response now includes the objectId of the created object.
• If loading companies or environments fails during the connect flow, the end user is now redirected to your cancelCallbackUrl instead of seeing an error page.

Changes:

• GET /dimensions in v1 now returns the same response as v2: a list of dimension categories. Use GET /dimensions/:dimension to get the values of a category. This affects Exact Online, Twinfield and Microsoft Business Central.

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August 2026

New integration:

• Tripletex is now available via the Maesn Unified API

New endpoints:

Abacus

• GET /customers

Dinero

• GET /journalEntries
• GET /journalEntries/:id
• PUT /journalEntries

Fortnox

• GET /accounts

Lexware Office

• GET /accounts
• GET /items
• GET /items/:id
• POST /items
• PUT /items
• DELETE /items

Procountor

• POST /bookingProposals
• POST /expenses

Tripletex

• GET /taxRates

Visma e-conomic

• GET /journalEntries
• GET /journalEntries/:id
• POST /journalEntries
• PUT /journalEntries
• GET /taxRates

Improvements:

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

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July 2026

New integration:

• Procountor is now available via the Maesn Unified API

New endpoints:

Buchhaltungsbulter

• GET /creditNotes
• GET /creditNotes/:id
• GET /creditNotes/:id/documents

Lexware Office

• POST bookingProposals/async

Odoo

• GET /invoices
• GET /invoices/:id

Procountor

• GET /accounts
• GET /contacts
• GET /taxRates

sevdesk

• POST bookingProposals/async

Snelstart

• POST /creditNotes

weclapp

• GET /bills
• GET /bills/:id
• GET /bills/:id/documents
• GET /creditNotes/:id/documents

Xero

• POST /bookingProposals

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June 2026

New integration:

• Dinero is now available via the Maesn Unified API

New endpoints:

Abacus

• GET /contacts/async
• GET /projects/async

Dinero

• GET /accounts
• POST /journalEntries
• GET /taxRates

Lexware Office

• GET /creditNotes
• GET /creditNotes/:id
• GET /creditNotes/:id/documents

Microsoft Business Central

• GET /bills
• GET /JournalEntries/async
• GET /openItems
• POST /payments
• GET /taxRates

Sage active

• GET journalEntries/:id/attachments
• GET journalEntries/:id/attachments/:id
• POST journalEntries/:id/attachments

sevdesk

• GET /creditNotes
• GET /creditNotes/:id
• GET /creditNotes/:id/documents

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May 2026

New endpoints:

Buchhaltungsbutler

• GET /bills/:id/documents

DATEV Unternehmen Online

• POST /bookingProposals/async

Lexware Office

• POST /expenses
• POST /payments

Microsoft Business Central

• POST /bookingProposals
• GET /invoices/:id/lineItems
• GET /invoices/:id/lineItems/:id
• POST /invoices/:id/lineItems
• PATCH /invoices/:id/lineItems

Sage active

• GET /journalEntries/:id/attachments
• GET /journalEntries/:id/attachments:id
• POST /journalEntries/:id/attachments

sevdesk

• GET /bills/:id/documents

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April 2026

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

• POST /files/async
• POST /expenses/async

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

• POST /bookingProposals (type INVOICE_CREDIT_NOTE)

Buchhaltungsbutler

• GET /bills
• GET /bills/:id
• GET /bookingProposals
• GET /bookingProposals/:id

sevdesk

• GET /bills
• GET /bills/:id
• GET /bookingProposals
• GET /bookingProposals/:id