Nexiun
All-in-one productivity hub for developers and students
thelawin.dev E-Invoicing API
Generate ZUGFeRD, Factur-X & XRechnung from JSON
@steviee
Follow on
Categories
Target Audience
Featured in
About thelawin.dev E-Invoicing API
thelawin.dev is a developer-first API for generating EU-compliant e-invoices from clean JSON. It returns valid PDF/A-3 invoices with embedded XML for ZUGFeRD 2.4, Factur-X 1.0.8 and XRechnung 3.0.2, plus XML-only formats like UBL, CII, Peppol and FatturaPA.
It is built for SaaS products, ERP tools, billing workflows and AI agents that need invoicing without handling PDF/A, EN 16931 or country-specific e-invoicing details themselves. The API is stateless by design: invoice data is processed into a response and not stored. Use it via REST, SDKs or the MCP endpoint for agent workflows.
Product Insights
thelawin.dev E-Invoicing API is a developer-centric fintech tool that transforms JSON data into EU-compliant invoice formats through REST, SDKs, and MCP endpoints. It enables the creation of PDF/A-3 and XML files across standards like ZUGFeRD 2.4 and XRechnung 3.0.2 without data storage.
- Native MCP server support allowing AI agents and LLMs to call invoicing functions directly.
- Stateless design ensures data privacy by processing invoices without persisting data.
- Broad compliance with EU standards including ZUGFeRD, Factur-X, XRechnung, and Peppol.
- Multi-platform availability via Web, REST API, and native SDKs.
Ideal for: This tool is ideal for developers, startups, and founders needing to automate EU-compliant invoicing within SaaS products, ERP systems, or AI-driven billing workflows.
Product Video
Screenshots
Product Updates (1)
@stevieeMay 6, 2026
thelawin.dev is now AI-First!
Quick build-log for the community. Over the past few weeks I rebuilt thelawin.dev (an e-invoicing API for ZUGFeRD, XRechnung, Factur-X, FatturaPA and Peppol) around AI-first principles. Here's what that actually means:
MCP server, not just REST. There's a new /mcp endpoint speaking JSON-RPC 2.0. Claude Desktop, ChatGPT agents and Cursor can register the API as a native tool. No OpenAPI mapping, no glue code. The model calls generate_invoice like any other function, with typed parameters and zero prompt-engineering ceremony around it.
llms.txt as first-class documentation. /llms.txt ships a machine-readable description of the API: which formats exist, when you'd pick each one, which fields are mandatory per country. An agent doesn't have to guess the schema, and it stops hallucinating field names within the first call.
Auto-format detection. JSON in, the right format out. Italy → FatturaPA. France → Factur-X. German B2G → XRechnung. The agent doesn't need to know which format is mandatory where; the API decides based on country and recipient type.
What changed in daily use. Yesterday I told Claude Desktop: "grab the order from email XY and turn it into a ZUGFeRD invoice as PDF." It worked. No Zapier, no custom integration, no webhook plumbing. That was the moment I realised this is where bookkeeping tools want to go in 2026 — not into yet another UI.
Beta still on. 50% off Starter (€9.50) and Pro (€24.50) until end of Q2. Sandbox is free with a watermark if anyone wants to poke at it.
Question for you. If you were to plug an e-invoicing API into an AI workflow, what would matter most? Generation, validation, or reverse parsing (PDF → JSON)? Curious to hear takes.
- Stephan
Product had at the time: 9 upvotes • 1 comments • 9 followers • 12 PeerPush
Comments (0)
No comments yet. Be the first to share your thoughts!
Reviews (0)
No reviews yet. Be the first to rate this product!
Explore highly rated
You may also like
Spanora
See what AI agents do and what they cost
Comments (1)
Generating ZUGFeRD, Factur-X, and XRechnung from simple JSON is a huge deal for developers dealing with EU e-invoicing compliance. This saves days of reading spec docs and implementing parsers.