lexware-mcp

Lexware Office is a German accounting software product, and this project builds a bridge between that software's API and AI assistants like Claude and ChatGPT. The bridge uses a protocol called MCP (Model Context Protocol), which is a standard way for AI tools to call external services. Once you run this server and connect it to an AI assistant, you can ask that assistant questions about your invoices, contacts, and bookkeeping records, and optionally have it create or update documents on your behalf.

The server is self-hosted, meaning you download it, run it on your own computer or a cloud container, and supply your own Lexware API key. It never stores credentials for anyone else. It comes packaged as a Docker container, so you can start it locally in a few commands or deploy it to any hosting platform that runs containers, such as a VPS, Fly.io, or Google Cloud Run.

There are 65 tools organized into three tiers. The read tier is always on and covers contacts, articles, invoices, quotations, credit notes, vouchers, payments, and PDF exports. The drafts tier, which is on by default, lets the AI create and update draft documents, upload files, and attach receipts to bookkeeping vouchers. The finalize tier is off by default and must be explicitly enabled: it allows the AI to issue legally binding documents that cannot be undone, so the README flags this clearly and warns that you are responsible for the legal and tax correctness of anything finalized.

For authentication, you can choose between two approaches. OAuth 2.1 works with the Claude web app and ChatGPT, which require a proper sign-in flow. A simpler static token approach also works, but only with Claude Code or Claude Desktop, which support custom request headers. You configure the server's behavior entirely through environment variables, including which tiers are enabled and whether the server runs in read-only mode.

The project is open source under the MIT license and links to two related projects that take a different approach to the same Lexware API using a local rather than network-based server style.