E-Invoice MCP Server

MCP Server for e-invoices in the DACH region — create, validate, and extract data from XRechnung. Directly from Claude, Cursor, or any MCP client.

What is this?

E-Invoice MCP is a Model Context Protocol server for creating and validating e-invoices according to the German XRechnung standard. Starting in 2027, all companies in Germany must be able to send e-invoices — this tool ensures you are prepared.

You simply tell Claude: "Create an invoice for Example GmbH for 10 hours of consulting" — and you receive a valid XRechnung as UBL 2.1 XML.

Related MCP server: mcp-facturacion-electronica-es

Features

• Create XRechnung — Valid UBL 2.1 XML from structured data (EN 16931 + XRechnung 3.0.2)

• Validate e-invoice — Check syntax, mandatory fields, and German business rules (BR-DE)

• Extract data — Read structured data from UBL or CII XML

• Format info — Reference guide for mandatory fields, tax categories, unit codes, and deadlines

• Automatic calculation — Net, gross, and tax amounts are calculated automatically

• Plugin-ready — Can run standalone OR be integrated into the BuchPilot MCP server

• No external services — Everything runs locally, no API keys required

• No native dependencies — Runs on any system with Node.js

Legal Deadlines

Incorrect e-invoices can lead to the loss of input tax deduction (+ 6% interest).

Installation

Prerequisites

• Node.js >= 18

npm (global)

npm install -g einvoice-mcp

From source

git clone https://github.com/makririch/einvoice-mcp.git
cd einvoice-mcp
npm install
npm run build

Configuration

This MCP server requires no configuration. No API keys or external services are needed — everything runs locally.

Usage

Start server (standalone)

# Nach npm install -g:
einvoice-mcp

# Oder von Source:
npm start

# Entwicklung mit Auto-Reload:
npm run dev

The server runs via stdio and waits for MCP messages.

Use in Claude Desktop

See Claude Desktop Setup Guide for detailed instructions.

Short version — add to claude_desktop_config.json:

{
  "mcpServers": {
    "einvoice": {
      "command": "npx",
      "args": ["-y", "einvoice-mcp"]
    }
  }
}

Examples (natural language in Claude)

After configuring the server, you can ask Claude, for example:

• "Create an XRechnung for Example GmbH for 10 hours of consulting at 150 EUR"

• "Is this XML file a valid XRechnung?"

• "Extract the invoice data from this XML"

• "What mandatory fields do I need for an XRechnung?"

• "What tax categories exist and what do they mean?"

• "By when must my company be able to send e-invoices?"

Quickstart

A step-by-step guide "Create your first XRechnung in 5 minutes" can be found in docs/quickstart.md.

Tool Reference

A complete reference of all 4 tools with parameters, example inputs, and example outputs can be found in docs/tool-reference.md.

Quick Overview

BuchPilot Integration

E-Invoice MCP can be integrated as a plugin into the BuchPilot MCP Server:

import { registerEInvoiceTools } from "einvoice-mcp";
registerEInvoiceTools(server);

Combination: BuchPilot creates an invoice in Lexoffice -> extract data -> generate XRechnung -> finished e-invoice.

Supported Standards

FAQ / Troubleshooting

"XML could not be parsed"

• Is the XML well-formed? (Are all tags closed correctly?)

• Is it actually a UBL or CII invoice? (Root element must be <Invoice> or <CrossIndustryInvoice>)

• Is the encoding UTF-8?

Validation shows error "BR-DE-13: Buyer Reference is mandatory"

The buyer reference (BT-10) is mandatory in XRechnung. For invoices to public authorities, this is the Leitweg-ID. For B2B invoices, it can be any reference (e.g., purchase order number).

{
  "buyerReference": "04011000-12345-67"
}

Validation shows warning "BR-DE-21: Phone number recommended"

This is just a warning, not an error. The invoice is still valid. For best compatibility, however, you should provide a phone number for the seller.

What tax categories exist?

What unit codes exist?

Server starts, but Claude does not recognize the tools

• Check if claude_desktop_config.json is correct

• Restart Claude Desktop after configuration changes

• Check the logs: ~/Library/Logs/Claude/mcp.log (macOS)

License

MIT — Free to use, including commercially.

Author

MaKri — GitHub