01 · Mix
Workstation and cloud treated as one query
DATEVconnect answers on the machine that runs DATEV. accounting:dataexchange answers from data already provided to the DATEV data centre. They are not the same posting.
DATEV API: the agent reads one posting and does not send the booking.
The DATEV API an agent can call is two documented doors. DATEVconnect serves account postings on the workstation, and only with the paid Kontobuchungen licence. The cloud gateway serves accounting sequences once the books have been provided to the DATEV data centre. Pexon does not let the agent post a booking.
Three ways a DATEV agent corrupts the books
02 · Licence
The free API is assumed to include the postings
The diagnostics guide says the DATEVconnect base licence is free. Account postings need the paid Kontobuchungen licence. Without it the read is empty.
03 · Post
The agent sends the batch
accounting-sequences and accounting:documents exist to hand postings and document images to DATEV. A tool with that right will use it.
Read 6 October 2026
Three DATEV API doors, and only two are reads
01
DATEVconnect, on the workstation
Local REST. The diagnostics guide says the DATEV workplace and the calling application share a machine. Account postings need DATEVconnect Kontobuchungen. A community answer documents the call under clients and fiscal-years on localhost port 58454.
02
accounting:dataexchange, after the books were provided
Interface requirements 1.0, first published 11 May 2026. Documented reads include the fiscal year, the chart of accounts, accounting sequences and terms of payment. DATEV marks it mandatory to tell the tax adviser what those reads are for.
03
Accounting API, the write that stays shut
Version 1.7.4. accounting-sequences can hand a batch in and read it back. accounting-records are the lines inside a batch. accounting:documents sends an image to Belege online. None of that is an agent action.
What a question is allowed to touch
Postings, sequences, document types
Local
Account postings
DATEVconnect, paid Kontobuchungen licence, one client and one fiscal year. This is the read a clerk already has on that workstation.
Provided
Accounting sequences
Cloud, only after movement data has been provided to the data centre. A missing sequence means the provision job has not run, not that the year is empty.
Metadata
Document types
Belege online, the step the Buchungsdatenservice use case puts before any image is transferred. The type list is a read. The image is not.
Use cases
Which DATEV API call holds which question
| Question | Door | Agent |
|---|---|---|
| What was posted for this client in this fiscal year? | DATEVconnect account-postings | Read, if Kontobuchungen is licensed on that workstation |
| Which batches were provided to the data centre? | accounting:dataexchange, accounting-sequences | Read, and the adviser is told why |
| Which document types can an image use? | Belege online metadata | Read the types. Do not send the image |
| Book this invoice | accounting-sequences and accounting:documents | No tool. A person confirms a draft in DATEV |
Developer Portal pages and one DATEV Community thread, read 6 October 2026. The localhost path is the community answer, not an OpenAPI file we opened.
Policy, not a live call
The first line is the person. The allow list is the reads the portal already names. The deny list is the batch and the image.
caller: the DATEV user who asked
allow: account_postings, accounting_sequences, document_types
deny: post_sequence, send_document
tell_adviser: required for dataexchangetell_adviser is not optional copy. The data-exchange requirements mark the explanation as mandatory.
Questions worth a tool, and the ones that stay in DATEV
Worth a named read
- Account postings for one client and one fiscal year, on DATEVconnect.
- Accounting sequences already provided to the data centre.
- Document types Belege online already lists.
Stays with a person
- Posting a batch, a cost sequence, or a document image.
- Opening a client the asking user cannot open.
- A cloud read the tax adviser has not been told about.
Handing bookings from an ERP to the adviser is the Buchungsdatenservice, and DATEV maintains it. An assistant outside DATEV is a different job, and it starts as a read.
What the DATEV administrator will check first
- The shop order, not the brochure. Kontobuchungen and Dokumentenmanagement are separate from the free base. A pilot scoped on DATEVconnect alone has no postings.
- Provision is a job someone runs. accounting:dataexchange sees movement data after it has been provided to the data centre. The interface does not reach into a workstation that never ran that job.
- No grant name on the pages we read. Cloud calls start with a permission check. The blueprint confirms the grant on your tenant. This page does not invent one.
When the vendor path is the right buy
If the only need is to pass bookings and document images from an ERP to the tax adviser, the Buchungsdatenservice already does that. Build the agent when someone is re-typing a posting into a chat. The tool list for that build is the DATEV integration.
The same question on a different suite
- DATEV integration — the tool manifest, the licences, and the reads that stay shut
- BMD NTCS integration — Austrian accounting suite, a different vendor and a different interface
- Utility billing for agents — the same rule on a Stadtwerk contract: read, do not send the market message
What the finance team will ask
Is there one DATEV API for everything in the books?
No. DATEVconnect is a local REST service on the workstation that runs DATEV. accounting:dataexchange and the Accounting API are cloud calls through the DATEV API gateway. A posting you can see on the workstation is not the same object as a sequence that has been provided to the data centre.
Which DATEV API call returns the account postings?
DATEVconnect, and only with the paid Kontobuchungen licence. A DATEV Community answer documents GET http://localhost:58454/datev/api/accounting/v1/clients/{client-id}/fiscal-years/{fiscal-year-id}/account-postings/ . The free base licence does not include that endpoint. Document management is a further paid licence.
Can the agent send a booking or a document image?
The APIs can. accounting-sequences accepts a posting batch, and accounting:documents sends an image to Belege online. This design refuses both as agent tools. A person confirms a draft in DATEV. A cloud read also has to be explained to the tax adviser, which the data-exchange requirements mark as mandatory.
What does it cost to find out which door your tenant actually has?
A two-week Readiness Blueprint at €4,900 net. We check the DATEVconnect licence, whether movement data is being provided to the data centre, and which of the documented reads your user can call. A first production server, once that list exists, is usually a use-case pilot from €15,000.
Next step
Open one DATEV client and name the first read
Two weeks. Bring the licence list and one client the test user may open. We tell you which of the three doors answers, and which questions are still the adviser's.