CII (Cross Industry Invoice)

Short definition

CII (Cross Industry Invoice) is an XML syntax for invoices published by UN/CEFACT — the UN body for trade and economic standards. CII is designed to be cross-industry: one syntax that works for manufacturing, trade, the public sector and services alike.

Together with UBL, CII forms the technical foundation of the European standard EN 16931 for e-invoices.

Structure of a CII document

A CII document has three main sections under the root element CrossIndustryInvoice:

<rsm:CrossIndustryInvoice xmlns:rsm="urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100">
  <rsm:ExchangedDocumentContext>
    <!-- profile, business process -->
  </rsm:ExchangedDocumentContext>
  <rsm:ExchangedDocument>
    <!-- invoice number, date, type -->
  </rsm:ExchangedDocument>
  <rsm:SupplyChainTradeTransaction>
    <!-- line items, contract data, payment terms -->
  </rsm:SupplyChainTradeTransaction>
</rsm:CrossIndustryInvoice>

The actual structure is noticeably more nested than UBL — CII consistently uses typed namespaces (ram:, udt:, qdt:) and separates document context from the underlying business transaction.

CII vs. UBL

Both syntaxes carry the same Business Term (BT) fields from EN 16931 — they are equivalent in content. Differences:

	CII	UBL
Publisher	UN/CEFACT	OASIS
Style	verbose, strongly typed	flatter, tag-oriented
Commonly used in	DE/AT/CH, France	Benelux, Nordics, Peppol
Basis for	ZUGFeRD, Factur-X	Peppol BIS Billing 3.0

Where CII is used

• ZUGFeRD (all versions) and Factur-X — the embedded XML in hybrid PDFs is CII
• XRechnung — CII is one of the two accepted syntaxes
• Peppol — technically possible, in practice almost always UBL

Generating CII invoices with the Dokmatiq API

curl -X POST https://api.dokmatiq.com/v1/einvoice/xrechnung \
  -H "Authorization: Bearer $DOKMATIQ_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "syntax": "CII",
    "invoice": { "id": "2026-0042", "issueDate": "2026-04-17", ... }
  }'

The API returns EN 16931-compliant CII XML validated against the official Schematron. If UBL is required, switch to "syntax": "UBL" — the semantic definition stays identical, only the XML mapping differs.

Common pitfalls

1. BT fields incomplete — CII is strongly typed and missing mandatory fields surface immediately during validation
2. Missing namespace prefixes — many parsers only accept the official prefixes (rsm:, ram:, udt:, qdt:)
3. Profile confusion — the CII in ZUGFeRD MINIMUM carries fewer fields than EN 16931, even though the structure looks the same