#cii

A complete developer reference for Factur-X — the hybrid PDF/A-3 + CII XML format used across France, Germany, and Luxembourg. XML anatomy, profile hierarchy, EN 16931 rule mapping, validation errors, and code samples.

EN 16931 supports two XML syntaxes: UBL 2.1 and UN/CEFACT CII. Here's when to use each, how they differ technically, and why it matters for validation.

Factur-X and ZUGFeRD are technically the same format with different names. But the details matter when you're trying to pass validation. Here's what you need to know.

ZUGFeRD and XRechnung are Germany's two e-invoice formats — but they solve different problems. This guide covers the XML structures, validation rules, profile mappings, and integration patterns ERP developers need to choose the right format.