German e-invoices over MCP, HTTPS, and API keys

German e-invoicing for AI agents.

Fakturai generates German B2B e-invoices as ZUGFeRD / Factur-X PDFs with structured XML through one hosted MCP server and REST API.

For Claude, Cursor, n8n, Make, Zapier, and backend services: EN 16931, German-market vocabulary, technical checks before delivery, and readable error reports instead of broken invoices.

Connect the MCP serverView API docs
Generation checks before delivery
EN 16931 + ZUGFeRD / Factur-X
Works with Claude, Cursor, n8n, any MCP client
MCP Server

Connect the remote MCP server

facturai exposes a hosted Streamable HTTP MCP server at https://fakturai.de/mcp. Use OAuth for interactive clients or a long-lived API key for servers and automations.

What you need

MCP URL

https://fakturai.de/mcp

Auth mode

OAuth for users, bearer API key for automation

Env var

FACTURAI_API_KEY

Tools

generate_einvoice, validate_einvoice, compliance_status

Response

PDF + XML payload or validation/error report

{
  "mcpServers": {
    "facturai": {
      "url": "https://fakturai.de/mcp",
      "authorization": {
        "type": "oauth"
      }
    }
  }
}

Authentication: OAuth for user-facing MCP clients, or Authorization: Bearer <FACTURAI_API_KEY> for long-running agents, n8n workflows, and backend services.

Available tools

generate_einvoice

Generate a ZUGFeRD / Factur-X invoice checked before delivery

Input: seller_profile, invoice_jsonReturns: PDF (base64) + validation report
validate_einvoice

Validate an existing invoice against German e-invoice rules

Input: content (PDF base64 or XML), content_formatReturns: Validation status, findings, hard failure count
compliance_status

Service readiness and compliance status for automation

Input: (none)Returns: Component versions, outdated flags

REST API example

Not using MCP yet? Call the same generation path from a backend or n8n workflow.

curl https://fakturai.de/api/invoices/generate \
  -H "Authorization: Bearer $FACTURAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "seller_profile_id": "default",
    "buyer": {
      "name": "Acme GmbH",
      "country": "DE",
      "vat_id": "DE123456789"
    },
    "line_items": [
      {
        "description": "Software development",
        "quantity": 8,
        "unit_price": 150,
        "vat_rate": 19
      }
    ],
    "due_days": 14
  }'

Example: generate an invoice in Claude

You say to Claude:

"Generate a ZUGFeRD invoice for Acme GmbH for 8 hours of software development at €150/h, invoice date today, due in 14 days. My seller profile is in my config."

facturai returns:

{ "success": true, "invoice_number": "ACME-20260604-141522", "validation_report": { "passed": true, "validation_status": "passed", "hard_failures": [] } }
Standards

The standards landscape without the jargon

German e-invoicing has layers: EU content rules, German exchange formats, and technical validation. You do not need to know every acronym to send a file your buyer can process.

Core standard

EN 16931

The rulebook

The European rulebook for e-invoice content: buyer, seller, VAT, payment terms, line items, totals, and validation rules. facturai generates EN 16931-aligned CII data so the invoice has the structure German B2B systems expect.

What facturai generates

ZUGFeRD 2.3

German hybrid PDF

The German name for the hybrid PDF format buyers can actually use: a readable PDF/A-3 with the machine-readable Factur-X XML embedded inside. Humans read the PDF, accounting systems ingest the XML.

Same as ZUGFeRD

Factur-X

Franco-German hybrid

The same hybrid PDF/XML format under the Franco-German name. If your customer, ERP, or accounting tool asks for Factur-X, that maps to the same ZUGFeRD-style output facturai generates.

B2G only

XRechnung

B2G strict variant

The stricter German B2G profile for invoices to federal, state, and municipal authorities. For normal B2B invoices, facturai reports XRechnung findings as advisory guidance instead of treating every public-sector rule as a delivery blocker.

Delivery gate

Technical validation

Format checks before delivery

facturai checks the invoice structure, embedded XML, totals, VAT data, and PDF/A layer before delivery. Files are returned only after they pass; failures return a readable error report instead of a broken invoice.

Mandate timeline: Wachstumschancengesetz

Jan 2025

All German businesses must be able to RECEIVE e-invoices.

Jan 2027

Businesses with >€800k revenue must ISSUE e-invoices.

Jan 2028

Remaining German B2B businesses must ISSUE e-invoices.

Free SEO tool

Already have an e-invoice? Check it on the validator page.

The homepage is for the hosted MCP server and generation API. The free validator remains available as a separate tool for uploaded ZUGFeRD / Factur-X PDFs and XML files.

Quick links

Pricing

Start free. Scale when it counts.

The validator is always free. Choose a subscription package or pay per generated invoice.

Free

Free/ validator

Check existing files without creating an account.

  • Unlimited invoice validation
  • Technical e-invoice checks
  • PDF/A compliance check
  • No account required
Use the validator

Pay as you go

€0.09/ per invoice

Best for low or spiky generation volume.

  • Metered generation billing
  • No monthly minimum
  • MCP server access
  • REST API
  • PDF + CII XML output
  • Scoped API keys
Create API key

Starter

€29/ month

Best for predictable recurring invoice volume.

  • 500 invoices included
  • €0.05 per extra invoice
  • MCP + REST API
  • Team API keys
  • Usage overview
Start subscription

Business

€99/ month

Best for higher-volume teams and automation workflows.

  • 2,500 invoices included
  • €0.03 per extra invoice
  • MCP + REST API
  • Team API keys
  • Priority onboarding
Start subscription

Subscription and metered billing are both available for testing. Signup creates an API key; subscription checkout starts payment for included monthly volume. See what gets checked.