Factur-X Validator API

Factur-X (also known as ZUGFeRD in Germany) is a hybrid format: a PDF/A-3 with embedded UBL/CII XML. It's mandated by the French B2B e-invoicing reform starting September 2026 and is one of the two formats Germany's 2025 mandate accepts (alongside XRechnung).

France B2B mandate timeline

• · Sept 1, 2026 — every B2B business must be able to receive e-invoices, and large & mid-size enterprises must send them
• · Sept 1, 2027 — small and micro businesses must also send
• · Invoices flow through certified private platforms (plateformes de dématérialisation partenaires, PDP) registered with the public invoicing directory — the PPF / Chorus Pro is the B2G portal and the directory, not a B2B transmission channel

What we validate

• · Factur-X 1.08 / ZUGFeRD 2.4 profile conformance (MINIMUM, BASIC WL, BASIC, EN 16931, EXTENDED)
• · Embedded UN/CEFACT CII XML against the EN16931 and profile schemas
• · EN16931 schematron rules
• · PDF/A-3 conformance
• · Embedded XML matches PDF metadata (cross-document consistency)

German callers know this format as ZUGFeRD — same format, same engine. Use ?format=factur-x or the alias ?format=zugferd; both the hybrid PDF/A-3 and the embedded CII XML on its own are accepted.

The validator is Mustang 2.23.0, maintained by Jochen Stärk and the FNFE-MPE working group in coordination with FeRD (Germany). Mustang reads the embedded XML straight out of the PDF/A-3 container for you — the phive reference engine validates only the XML you extract yourself.