For finance teams and tax advisers on DATEV
A DATEV MCP server gives an assistant named reads on DATEV Rechnungswesen: local DATEVconnect account postings, and cloud accounting sequences through the DATEV API gateway. DATEV publishes no MCP server as of 6 October 2026. Posting a booking stays with a person in DATEV. Pexon builds the server against the installation and the licences you already hold.
Why DATEV is hard for agents
01 · Two doors
DATEVconnect answers from the machine that runs DATEV. accounting:dataexchange answers from data the user has already provided to the DATEV data centre. A tool that treats them as one login will mix a live posting with a provided extract.
02 · Licence
The diagnostics guide says the DATEVconnect base licence is free, and the accounting-postings endpoints need a separate paid licence, DATEVconnect Kontobuchungen. A pilot that skips the shop order gets an empty read.
03 · Adviser
DATEV's data-exchange requirements mark it mandatory: if the chart of accounts, accounting sequences or terms of payment are used, tell the DATEV adviser what they are used for. The connector does not hide that.
04 · Posting
accounting-sequences and accounting:documents exist to send postings and document images. Those are not agent tools. The only write in the manifest is a draft a person confirms in DATEV.
Checked 6 October 2026
| What we found | |
|---|---|
| Interfaces | DATEVconnect accounting (local REST, docs public) · accounting:dataexchange (REST via DATEV API gateway, docs public) · DATEV Accounting API (REST, docs public) |
| Authentication | DATEVconnect is a desktop API on the same machine as the DATEV workplace, which the diagnostics guide states explicitly. Cloud calls go through the DATEV API gateway. The data-exchange workflow starts by checking permissions; the pages read on 6 October 2026 do not publish a grant name, so the blueprint confirms the grant on your tenant rather than assuming one. |
| Vendor MCP server | No vendor server. No DATEV MCP server is described on the DATEV Developer Portal pages read on 6 October 2026. |
| Vendor AI assistant | None found. |
| Other connectors | None found. |
DATEV eG (DE). German tax advisers and the companies whose books they keep in DATEV Rechnungswesen, plus in-house finance teams on DATEV. The pages read on 6 October 2026 describe the interfaces, not a customer count.
What we build
Built on what DATEV eG documents: clients, fiscal years, account postings, accounting sequences, accounting records, chart of accounts and personal accounts, terms of payment, posting proposals. Backends named below are documented resources; "confirmed in blueprint" means the vendor documentation sits behind a login and the resource is checked against your release first.
# datev-mcp-server: tool manifest, draft for blueprint week 1
# Every tool runs as the person asking. Nothing is written without a person confirming.
tools:
list_clients: # the signed-in user -> Rechnungswesen clients the user may open
backend: accounting:clients
mode: read
get_account_postings: # client, fiscal year -> account postings on the workstation
backend: DATEVconnect GET account-postings, paid Kontobuchungen licence
mode: read
list_accounting_sequences: # client, fiscal year -> sequences provided to the data centre
backend: accounting:dataexchange GET accounting-sequences
mode: read
list_document_types: # client -> document types Belege online already has
backend: Belege online metadata, step 2 of the Buchungsdatenservice use case
mode: read
draft_posting_batch: # client, records -> a batch preview a person confirms in DATEV, never posted by the agent
backend: accounting-sequences, confirmed in blueprint
mode: propose
audit: every call logged with user, tool, arguments and the DATEV responseThe manifest is the contract. A question that needs an operation not on it gets a new line and a review, not a wider permission.
One interface per row
01
local REST. Documentation is public. runs on the workstation where DATEV is installed. The base DATEVconnect licence is free from the DATEV shop; reading account postings needs the paid DATEVconnect Kontobuchungen licence, and document management needs the paid DATEVconnect Dokumentenmanagement licence. A DATEV Community answer gives the account-postings call as GET http://localhost:58454/datev/api/accounting/v1/clients/{client-id}/fiscal-years/{fiscal-year-id}/account-postings/
02
REST via DATEV API gateway. Documentation is public. movement data from DATEV Rechnungswesen, after the user has provided it to the DATEV data centre. Interface requirements 1.0, first published 11 May 2026. Documented reads include fiscal year, chart of accounts, accounting sequences and terms of payment. DATEV marks it mandatory to tell the tax adviser what those reads are for
03
REST. Documentation is public. accounting-sequences hand a posting batch to DATEV Rechnungswesen and can be read back; accounting-records are the postings inside a batch; posting-proposals carry invoice data; accounting:documents sends a document image to Belege online. Version read: 1.7.4
DATEV holds the records. An assistant without a governed way in answers from whatever someone pasted into the chat. The connector is the governed way in: named operations, the person's own permissions, every call logged.
When this is the wrong page
If the only job is to hand bookings from an ERP to the tax adviser, DATEV's Buchungsdatenservice already does that and DATEV maintains it. A connector is right when an assistant outside DATEV has to answer a question about the books under the asking person's rights.
Two weeks, €4,900 fixed price. Week one agrees the tool list with your DATEV owners and checks every backend against your release and licence. Week two tests whether a person's own DATEV permissions reach through the connector. You keep the manifest and a costed build plan, whoever builds it. All prices are net and exclude VAT.
What we need from you: a named DATEV administrator, a test or sandbox system we may call, and one business owner who can say which questions the assistant should answer first. The first production connector is usually a use-case pilot from €15,000; it runs in your environment, and the code is yours.
Not on the DATEV Developer Portal pages read on 6 October 2026. DATEV publishes DATEVconnect for the workstation and cloud APIs for accounting sequences, documents and data exchange. An MCP server for an assistant outside DATEV has to be built against those, which is what this page describes.
For account postings on DATEVconnect, yes. The diagnostics guide says the base DATEVconnect licence is free from the shop, and the accounting-postings endpoints need the paid DATEVconnect Kontobuchungen licence. Document management is a separate paid licence. The blueprint checks which of those you already have before any tool is written.
No. accounting-sequences and accounting:documents exist so a partner system can send postings and document images. In this connector those stay with a person in DATEV. The only write is a draft the person confirms. A cloud read through accounting:dataexchange also has to be explained to the tax adviser, which DATEV marks as mandatory.
The two-week Readiness Blueprint is fixed at €4,900: agreed tool list, backends checked against your licences, identity tested end to end, costed build plan. The production connector is usually a use-case pilot from €15,000. Prices are net, excluding VAT.
Next step
Thirty minutes with the engineer who would build the connector, with your DATEV administrator in the room if you like.