Trusted by winning dev teams
Certified by DATEV
Maesn is officially certified by DATEV as Interface Partner. That means for you: You are whitelabel certified via Maesn!
"Maesn transformed the way how to integrate with DATEV. What would have been a complex direct integration turned into a smooth, intuitive process thanks to their REST API and DATEV sandbox. There are simply just upsides."
Thiago Peres
CTO @ getrally.com
Maesn's DATEV API advantage
Integrate to DATEV Unternehmen Online and DATEV Rechnungswesen with one unified API.
Whitepaper
Learn everything about DATEV
DATEV Coverage and Use-Cases
Our DATEV REST API covers all services with one API.
Upload receipts, invoices, PDFs & images directly via REST API.
Automated handover between Unternehmen Online and Rechnungswesen workflows.
Belegbilderservice
Document Uploads
Sync outgoing & incoming invoices with normalized JSON.
Supports Rechnungsdatenservice 1.0 and Rechnungsdatenservice 2.0.
Rechnungsdatenservice
Invoice Data
Send fully structured booking entries into DATEV — error-mapped, validated, and standardized.
Buchungsdatenservice
Bookings
Pull bookings as Journal entries from DATEV.
New: Pull data
Pull bookings
Integrate with
Maesn API
Production
approval by Maesn
Certified
App
Learn more on DATEV APIs
Why companies choose Maesn
3 Reasons why integrate DATEV with Maesn
Certified & Compliant
Get a DATEV certified integration via Maesn. Our API is continuously tested, secured & maintained.
Post & Pull data
Post and Pull data via our REST API and forget about CSV/XML and services.
DATEV Sandbox
We provide DATEV sandboxes, enabling you to fully focus on you product.
Not for DATEV Unternehmen Online and DATEV Rechnungswesen.
DATEV provides Data Services based on CSV/XML. Maesn adds the REST API layer on top.A direct integration with DATEV means working with the native Data Services (BDS, RDS, BBS). These are not REST APIs. They rely on CSV/XML files, ZIP bundles, asynchronous handovers, separate interfaces per service, and custom DATEV validations. This makes implementation and long-term maintenance complex, slow, and fragile.
Maesn abstracts all of this into one unified REST API.
You work with clean JSON, consistent endpoints, automatic error mapping, a unified data model for DUO and DATEV Accounting, and modern authentication. Maesn handles the underlying DATEV logic, file formats, validations, and workflows in the background — fully certified by DATEV.DATEV Unternehmen Online (DUO) is the cloud platform used by businesses and accounting firms to upload documents, manage receipts, prepare payments, handle workflows, and collaborate digitally with tax advisors. It focuses on document management, OCR, payment data, and pre-accounting processes.
DATEV Rechnungswesen (also known as Kanzlei-Rechnungswesen or Rechnungswesen classic) is the core accounting system where the actual bookkeeping happens. This is where receipts are booked, accounting records are finalized, and financial statements are created.
DATEV does not offer a public sandbox or test environment.
In most cases, the only way to test a DATEV integration is to work with a tax advisor who can create a test client (Test-Mandant) inside their DATEV environment. This process is manual, requires coordination with a DATEV partner, and provides only limited testing capabilities.
With Maesn, you get immediate access to a fully functional DATEV sandbox.
We provide a dedicated test company with realistic test data, a stable REST API, predictable responses, and the same unified data model used in production. No tax advisor, no manual setup, no waiting times.In DATEV, each “company” is treated as a separate client (Mandant). Every client has its own access rights, its own authentication, and its own technical setup. Because DATEV does not offer a centralized multi-company API, you must establish a separate connection for every Mandant, including individual credentials, individual token flows, and individual data transfers for documents, invoices, or booking entries. This structure makes it difficult to scale if your product needs to connect many customer companies.
Maesn simplifies this completely. We abstract the DATEV client structure into a unified REST model that supports multiple companies natively. Instead of building and maintaining isolated integrations per Mandant, you work with a single API and switch between companies through a simple identifier. Onboarding becomes automated, the data model stays consistent for every company, and your system can scale across hundreds of DATEV clients without additional engineering work.
In most cases, DATEV does not allow data to be retrieved directly through its Data Services. The native interfaces focus primarily on uploading documents, invoices, and booking data into DATEV, not on reading information back out. As a result, direct integrations typically offer very limited or no read-access at all.
Maesn changes this. As an official technology partner of DATEV, Maesn is the only Unified API that provides structured, REST-based access to selected DATEV data and is continuously expanding this read scope. This enables SaaS products to synchronize information, display accounting data, and build richer workflows that go far beyond what the native DATEV interfaces allow.
Frequently Asked Questions