E-Invoice ValidatorCII
Cross Industry Invoice — the second EN 16931 syntax, basis of ZUGFeRD.
CII is the UN/CEFACT Cross Industry Invoice standard in version D16B and the syntax that ZUGFeRD and Factur-X use.
The root element is called CrossIndustryInvoice. The specification identifier BT-24 is in GuidelineSpecifiedDocumentContextParameter.
CII and UBL are technically equivalent: both represent the same EN 16931 data model, just with a different structure.
Rules that often fail here
See also
Status: 12.10.2026