EU e-invoice formats

What each format is, which country mandate requires it, and how InvoiceHub generates and validates it against the official EN 16931 rules.

• UBL 2.1
  XML (OASIS Universal Business Language)
  What UBL 2.1 is, who requires it, and how to generate an EN 16931-conformant UBL invoice from structured JSON.
• UN/CEFACT CII
  XML (UN/CEFACT Cross Industry Invoice, D16B)
  What Cross Industry Invoice (CII) is, who requires it, and how it relates to UBL and Factur-X.
• XRechnung 3.0
  UBL 2.1 or UN/CEFACT CII (both supported)
  Germany’s mandatory B2G e-invoice format: what it adds on top of EN 16931 core, and how to generate a conformant document.
• Factur-X / ZUGFeRD
  Hybrid PDF/A-3 with embedded UN/CEFACT CII
  The hybrid PDF+XML e-invoice format used in France and Germany: how it’s structured, and how to generate a genuinely PDF/A-3 conformant file.