What is CII? Format and uses explained

CII, the Cross Industry Invoice, is an XML invoice syntax published by UN/CEFACT, the United Nations trade facilitation body. EN 16931 publishes a syntax binding for CII D16B, alongside UBL 2.1 and UN/EDIFACT INVOIC D16B. Every ZUGFeRD and Factur-X file carries a CII XML inside, and XRechnung can be written in CII too.

What is in a CII invoice?

A CrossIndustryInvoice XML document can hold parties, lines, VAT, totals and payment terms in a different structure from UBL. CII is a syntax, not proof that an invoice meets EN 16931.

Property	Value
Maintained by	UN/CEFACT (UNECE)
Version used for EN 16931	D16B
European invoice-model binding	EN 16931 (European Commission)
File type	`.xml`, or embedded in a PDF/A-3

Which formats use CII?

Format	How
ZUGFeRD and Factur-X	CII inside a PDF/A-3
XRechnung	CII or UBL, as a plain XML file
French reform base formats	CII is one of three, with UBL and Factur-X

What can Klarbon do with CII?

Task	Tool
Read it, print it, save it as PDF	Open a CII invoice, free
Check the selected supported rule set, in beta	Check an e-invoice
Convert a structured e-invoice to CII	Convert an e-invoice

Reading plain PDF invoices is not available yet.

Frequently asked questions

Where will I meet a CII file?

Inside a ZUGFeRD or Factur-X PDF, or as a standalone XRechnung in CII syntax. It is also one of the formats the French reform accepts.

Is CII better than UBL?

Neither is better. Both are allowed by EN 16931. Use the one your customer or platform specifies. Peppol BIS Billing 3.0 uses UBL, not CII.

Which CII version is used for e-invoices?

EN 16931 publishes a binding for D16B, which Klarbon supports. Newer CII releases exist: the current Factur-X documentation uses D22B. Do not assume every CII release or profile is supported.

What is CII?