ZUGFeRD / Factur-X

ZUGFeRD and Factur-X are the same hybrid e-invoice concept under two national names: a PDF/A-3 file with EN 16931 XML embedded, so the document is both a readable PDF and a machine-readable e-invoice.

Hybrid invoices ease the transition to full e-invoicing because the recipient can read the PDF even if they don't yet process the XML. They are accepted in Germany and France during the move to mandatory structured invoicing.