Most European e-invoicing tools fall into two camps: heavyweight compliance suites priced for SAP customers, or fragmented open-source libraries with stale dependencies and no support. InvoiceXML is the developer-first middle ground: - One API, every major European format. Factur-X, ZUGFeRD, XRechnung, UBL, and CII. - Generate, validate, and convert between them through a single REST endpoint. - Human-readable errors built in. - AI-assisted PDF prefill. - Zapier, Make, PowerAutomate ready

A few months ago, I was working on a side project that needed to generate Factur-X invoices for French B2B customers. Easy, right? A hybrid PDF with embedded XML, follows EN 16931, well-documented standard. How hard could it be? If you've ever tried implementing this yourself, you already know the answer: surprisingly painful. The existing options came down to: 1. Pay thousands per year for an enterprise compliance suite that bundles a hundred features I didn't need. 2. Cobble together open-source libraries with stale dependencies and inconsistent validation behavior. 3. Build it from scratch and read 400 pages of UN/CEFACT CII specifications on a weekend. I picked option 3, mostly out of stubbornness.

InvoiceXML

Factur-X, ZUGFeRD, XRechnung, UBL. One API.

Factur-X, ZUGFeRD, XRechnung, UBL. One API.