UN/CEFACT CII D16B
The syntax inside Factur-X & XRechnungCross Industry Invoice (CII) D16B is the other EN 16931 XML syntax alongside UBL — a single-document schema that underlies both Factur-X/ZUGFeRD's hybrid PDF format and one of the two valid XRechnung syntaxes.
What it is
Where UBL splits invoices and credit notes into separate root elements, CII represents both as one CrossIndustryInvoice document distinguished by a type code. CrateAPI generates and validates plain CII XML directly — you don't need to go through Factur-X to get it.
Where it's mandatory
You rarely choose CII on its own — it shows up as the syntax inside Factur-X (France), as one of two valid XRechnung syntaxes (Germany), or when a trading partner's system is CII-native and you need to convert from UBL.
What we don't do. CII and UBL cover the same EN 16931 semantic model, just in different XML shapes — that's why conversion between them is lossless-or-rejected rather than a lossy best-effort guess.
Try it
curl -X POST "$BASE/v1/generate/cii?profile=en16931" \ -H "X-API-Key: $KEY" -H "Content-Type: application/json" \ -d @invoice.json -o invoice.xml
Relevant endpoints
| Endpoint | Notes |
|---|---|
POST /v1/generate/cii?profile=en16931|xrechnung | en16931 or xrechnung profile — same engine as the UBL side. |
POST /v1/validate/cii?profile=en16931|xrechnungfree | Official schematron + XSD rules, structured findings. |
POST /v1/convert/{ubl-to-cii,cii-to-ubl} | Lossless-or-rejected — 422 with the exact unsupported features, never a silent downgrade. |
POST /v1/render/{html,pdf} | CII auto-detected alongside UBL, no separate flag needed. |
Samples & docs
Download validated CII sample files (invoice and credit note) from our sample library, or read the full API reference.
FAQ
Should I use UBL or CII?
If you're free to choose, UBL/Peppol is the more common pan-EU default. Use CII when a trading partner requires it, or when you need Factur-X/ZUGFeRD or XRechnung's CII option.
Can I convert between UBL and CII?
Yes — POST /v1/convert/{ubl-to-cii,cii-to-ubl}, lossless-or-rejected: if a feature can't survive the conversion you get a 422 with the exact list, never a silently degraded invoice.
Does CII support credit notes?
Yes, the same document type with a different type code — see the CII group in our sample library for both an invoice and a credit note.