CII Cross Industry Invoice Format
CII, short for Cross Industry Invoice, is an XML invoice syntax developed by UN/CEFACT. In European eInvoicing it is important because it can carry EN 16931 invoice data and is also used inside hybrid invoice formats such as Factur-X and ZUGFeRD. This page explains what CII is, when businesses use it, and what matters during conversion to or from UBL, FatturaPA, and PDF outputs.
What CII Represents
A CII invoice describes a commercial transaction with structured XML sections for the document header, trade agreement, delivery, settlement, tax details, monetary totals, and line items. The same business concepts also exist in UBL invoices, but the syntax and nesting model are different, so conversion requires careful mapping rather than a simple rename of XML elements.
- Header data identifies the invoice, dates, currency, and document context.
- Trade party data describes the seller, buyer, tax registrations, and addresses.
- Settlement data contains payment terms, tax breakdowns, allowances, charges, and payable totals.
- Line data carries product or service descriptions, quantities, prices, taxes, and line totals.
Where CII Is Used
CII is common in European invoice interoperability because it is one of the syntaxes used for EN 16931-aligned invoices. It is especially visible in hybrid PDF workflows: Factur-X and ZUGFeRD documents normally contain a readable PDF plus embedded CII XML for automated processing.
Businesses may need CII when exchanging invoices with ERP platforms, public procurement systems, German or French hybrid invoice workflows, or customers that prefer CII over UBL for structured invoice intake.
CII Conversion Notes
| Conversion | Important Review Points |
|---|---|
| CII to UBL | Map trade party, tax, line, and settlement data into UBL invoice sections while preserving EN 16931 meaning. |
| UBL to CII | Translate UBL accounting supplier/customer parties, tax totals, legal monetary totals, and invoice lines into CII structures. |
| CII to FatturaPA | Check Italian fiscal identifiers, payment details, VAT information, and mandatory FatturaPA transmission fields. |
| CII to PDF | Create a readable invoice view while keeping totals, tax breakdowns, dates, parties, and line details clear for review. |
Validation Before Production Use
CII output should be checked for schema validity, mandatory business terms, tax consistency, rounding, currency, and target platform requirements. A technically valid XML file can still be rejected if a receiving system expects a specific profile, identifier, or country-specific business rule.