Connecting DATEV to Copilot, ChatGPT, or Claude: What works

The short answer

• DATEV offers no ready-made connection for Copilot, ChatGPT, or Claude. It hasn’t published an interface for outside AI assistants, and no MCP server either, the component such assistants use to query other software. DATEV’s own assistant, DATEV Copilot, is built for tax advisory firms and only works inside DATEV.
• Since April 2026, companies whose bookkeeping is done by a tax advisor can get their postings through a new DATEV service for exporting accounting data. The tax advisor has to set it up. The numbers reflect the last archive run, and open items aren’t included yet.
• Tax advisory firms get to their DATEV data fastest through a gateway provider such as Klardaten. Its MCP server reads more than 100 data areas and works with Copilot, ChatGPT, and Claude.
• Companies that run DATEV programs themselves can attach a custom MCP server through DATEV’s local interface, DATEVconnect, for reading and writing.

Why the German numbers are in DATEV

DATEV is a cooperative based in Nuremberg, founded by German tax advisors in 1966. Only members of the tax, accounting, and legal professions can join, around 40,000 of them as of 2025, and DATEV is the market leader for tax advisory software in Germany. When a German subsidiary has its bookkeeping done by a tax advisor (Steuerberater), the data is most likely in DATEV, either in the tax firm’s own installation or in DATEV’s data center.

A few German terms come up below. A Kanzlei is a tax advisory firm, which is why DATEV’s products for them carry the word. DATEV Unternehmen online is the web portal where the company uploads receipts and sees its reports. The BWA (betriebswirtschaftliche Auswertung) is the standard management report tax advisors produce from the books in DATEV.

DATEV Copilot is not Microsoft Copilot

A search for “DATEV Copilot” leads to DATEV’s own AI assistant, not Microsoft’s. It has been available since May 2026 in MyDATEV, DATEV’s customer portal, and DATEV describes it as the central AI assistant for tax advisory firms. It writes and translates text, summarizes uploaded documents of up to 1,000 pages, and searches the web, specialist databases, and DATEV’s help content. The basic license is free, while specialist research and the MyDATEV Kanzlei features need their own licenses. According to DATEV, processing happens in the DATEV cloud.

It helps with text and research, not with the travel expense question. DATEV says it can’t currently analyze structured data such as the BWA, tables, or other reports. DATEV also describes no connection to Microsoft 365 Copilot, ChatGPT, or Claude, neither for DATEV Copilot nor for its announced products.

Where the books are kept decides the route

• At the tax firm: the firm posts in DATEV Kanzlei-Rechnungswesen, and the company sees receipts and reports in DATEV Unternehmen online. The company can’t reach the tax firm’s programs, only what the firm provides in DATEV’s data center. This is the setup when a German subsidiary has its bookkeeping done by a tax advisor.
• In the company: some businesses do their own books with DATEV programs, on their own network or in DATEV’s cloud (DATEVasp, DATEV-SmartIT).
• In the tax firm, for the tax firm: then it’s about the data of all clients and the firm’s own work.

Behind this are two kinds of interfaces. DATEV’s online APIs run through its data center and reach data stored there. DATEVconnect is the interface of the installed DATEV programs, and according to DATEV it’s only available on the local network, not over the internet. Copilot, ChatGPT, and Claude can’t reach it on their own.

Five routes compared: three connect AI to DATEV

The gateway prices apply to annual billing (Klardaten, as of October 2026). The first and last routes aren’t connections: DATEV Copilot stays inside DATEV, and uploading the BWA once a quarter gets answers about exactly those numbers and nothing newer.

For companies: the tax advisor sets up the export service

On April 29, 2026, DATEV released the Datenservice Export Rechnungswesen, its data service for exporting accounting data. According to DATEV, it’s the first time accounting data can be retrieved directly and processed in other software. It provides account postings, fiscal year data, the chart of accounts, posting batch information, payment terms, and the trial balance, among other things. The API is called accounting:dataexchange.

Two limits decide whether that’s enough:

• The data comes from the last archive run in DATEV’s accounting archive, so it’s only as current as the tax firm’s archiving. DATEV requires archiving at year-end at the latest; some firms archive monthly along with the advance VAT return (Umsatzsteuer-Voranmeldung). With monthly archiving, the numbers work for year-to-date travel expenses, but not for yesterday’s receipts.
• Open items are missing. DATEV has been piloting them since the third quarter of 2026 and plans to release them in the first quarter of 2027. Until then, an assistant using this route can’t say whether a specific invoice has been paid.

The tax firm has to set up the service for its clients, through the MyDATEV client registration. Companies that do their own books in DATEV order it the same way. The software that retrieves the data needs an interface DATEV has approved. Running costs are in DATEV’s price list, and according to DATEV they’re usually paid by the end user, meaning the tax firm or the client.

DATEV’s interface rules generally don’t allow integrations that call its APIs around the clock without a specific request. An MCP server fits that model, because it only asks when someone wants to know something.

The older data services work in the other direction. They bring receipts, postings, and invoices from other software into DATEV, and since April 2026 e-invoices as well, through an interface to the DATEV e-invoicing platform. The article on Germany’s e-invoicing mandate covers what applies from January 2027.

A custom connection to DATEV’s data center rarely pays off

Connecting to the export service directly means going through the same process as a software vendor: create an organization in the DATEV Developer Portal, register an app, develop against the sandbox, then at least two release meetings by video call, first for the sandbox and then for production. Real clients and real data aren’t allowed in the review, and a DATEV test system is required. Onboarding alone costs €1,500 plus VAT, once, including four hours of consulting, and each additional hour is €210. According to DATEV, there’s no simplified process for internal, non-commercial use.

For a single company, software that already has the interface is the shorter route. In October 2026, DATEV’s marketplace lists more than ten such programs, Helu among them, for P&L, dashboards, and KPIs. Whether a program also passes the numbers on to an AI assistant is a question for its vendor. If a service provider does build the connection, DATEV recommends that the commissioning company create the organization in the Developer Portal itself and remain its owner, with the provider’s staff invited as members.

Open-source MCP servers for DATEV on GitHub aren’t a shortcut either. One of the newer ones is connected to the sandbox, according to its status note from October 22, 2026, and for real data it needs the same DATEV review as any other software.

For tax firms: a gateway makes DATEVconnect reachable

DATEVconnect can’t be reached from outside, and gateway providers close that gap. At Klardaten, a gateway runs in the tax firm’s DATEV environment, set up by the firm’s IT partner or, for DATEVasp, by DATEV. It exposes DATEVconnect as a hosted API, and Klardaten’s MCP server sits on top of it.

MCP, the Model Context Protocol, is an open standard. The MCP server determines which tools the assistant gets, for example one that searches postings and one that retrieves a document.

According to Klardaten, the server reads more than 100 data areas from accounting, document management, master data, order management, and payroll. It can also write: create clients and addresses, upload documents, and create posting batches that aren’t finalized yet. Each write permission is granted separately when connecting, and the permissions of the connected DATEV profile apply. Sign-in uses OAuth, and write actions are logged.

Microsoft lists the “Klardaten DATEV-Connector” in the Microsoft 365 Copilot connector gallery. Everyone who uses it there needs a Microsoft 365 Copilot license; the article on connecting business software to Copilot explains the setup in the admin center. Klardaten says the server also works with ChatGPT, Claude, Copilot Studio, Langdock, and n8n.

DATEV on the company network: a custom MCP server via DATEVconnect

The DATEV shop lists the DATEVconnect license at €0.00 per month (item no. 95280). It covers DATEV Kanzlei-Rechnungswesen, DATEV Mittelstand Faktura mit Rechnungswesen, Lohn und Gehalt (payroll), and the document archive, among others. In accounting, it exchanges master and transaction data and reads reports. A program that uses DATEVconnect signs in with a Windows user mapped to a DATEV user and gets exactly that user’s permissions.

A custom MCP server sits on the same network and gives the assistant only the tools it should have. For Copilot, ChatGPT, or Claude to reach it, the server has to be accessible from outside and secured; DATEVconnect itself stays on the local network. If DATEV runs in DATEV’s cloud, the part that talks to DATEVconnect has to be installed there. For DATEV-SmartIT, DATEV requires an add-on module for third-party connections (Zusatzmodul Anbindung Drittanbieter).

Nobody else carries the effort on this route: running the server, applying updates, logging access. In return, the company decides for itself what the assistant is allowed to do.

Data protection: a data processing agreement comes first

Accounting data contains the names of customers, suppliers, and employees. As soon as an AI provider processes it, the company needs a data processing agreement under Art. 28 GDPR with that provider, and with any gateway provider in between. Providers only offer one on certain plans, so that’s worth checking before the first upload or connection.

Tax firms also have a duty of confidentiality. Section 62a of the German Tax Advisory Act (StBerG) lets tax advisors give service providers access to client data only as far as the service requires, and only under a contract in text form that binds the provider to confidentiality and points out that a breach is a criminal offense. If the provider is abroad, the protection of secrets there has to be comparable. With a gateway, the retrieved data passes through the gateway provider to the AI assistant, and according to Klardaten the AI provider’s terms govern what happens to it there. Both belong in the review.

Which route fits

Up to four questions lead to the right route, with the reasoning below.

Checklist · Question 1 of 6

Should the assistant answer questions about the DATEV numbers on an ongoing basis?

For a single analysis, an export such as the BWA as a PDF is often enough. A connection pays off when the team keeps asking.

Checklist · Question 2 of 6

Who does the bookkeeping in DATEV?

That decides the interface: the online APIs through DATEV’s data center, or DATEVconnect, which is only available on the local network.

Checklist · Question 3 of 6

Should the assistant query DATEV together with other software?

For example, revenue from DATEV next to orders from the ERP or customers from the CRM. That takes a custom MCP server that brings both together.

Checklist · Question 4 of 6

What should the assistant answer?

DATEV’s export service provides postings, accounts, and balances as of the last archive run. Open items are planned for the first quarter of 2027.

Checklist · Question 5 of 6

Should the assistant query DATEV together with other software?

For example, revenue from DATEV next to orders from the ERP or customers from the CRM. That takes a custom MCP server that brings both together.

Checklist · Question 6 of 6

Where do the DATEV programs run?

DATEVconnect is only available on the local network. If DATEV runs in DATEV’s cloud, the part that talks to DATEVconnect has to be installed there.

If a tax firm keeps the books and the questions are about monthly and annual figures, I’d talk to the tax advisor about the export service and use software that already has the interface. Questions about incoming payments have to wait until open items are released.

If a tax firm wants to use client data in an assistant, a gateway with an MCP server is the shortest route, read-only at first. I’d only grant write permissions once it’s clear which questions the team actually asks.

If DATEV runs on the company’s own network, or the assistant should query DATEV together with other software such as an ERP, a CRM, or a document management system, a custom MCP server is worth it. It determines which tools exist, whether access is read-only, and what gets logged. That’s the work behind the Connecting software service.

For a one-off analysis, uploading the export is enough, as long as the AI provider’s plan includes the right agreement.

So for year-to-date travel expenses at the German subsidiary, the technical side is solvable. The first conversation still belongs with the tax advisor in Germany, who decides which data is available, how often it’s archived, and who gets to see it.