The European E-Invoicing standard (EN 16931) allows two technical formats (syntaxes) for electronic invoices: UBL (Universal Business Language) and CII (Cross Industry Invoice).
When your system generates a compliant CII XML document, it creates the raw, machine-readable data layer required by European law.
We are currently supporting two types of XML formats:
Peppol UBL (BIS 3.0)
CII (UN/CEFACT)
What is CII XML?
CII is an XML-based e-invoice format defined by UN/CEFACT (United Nations Centre for Trade Facilitation and Electronic Business). It is one of two valid syntaxes for the European E-Invoicing standard EN 16931, alongside UBL.
The standard is based on the UN/CEFACT D16B schema and offers a flexible, cross-industry solution for international business transactions.
What CII XML Supports?
European E-Invoicing (EN 16931) CII supports the requirements of EN 16931 and provides an alternative way to implement E-Invoicing.
Hybrid Invoice Formats (ZUGFeRD & Factur-X)
When you create a ZUGFeRD or Factur-X invoice, the embedded XML file uses CII syntax. The PDF provides human readability; the CII provides machine readability.
National Standards The CII syntax is mainly used for ZUGFeRD/Factur-X (Germany & France), as well as being the second permitted syntax in Germany for XRechnung.
Note: If your accounting software encounters any compatibility challenges with our CII XML file, please reach out to our support team available 24/7 with the error information. We are happy to review and adjust the data structure to match your specific business needs.
What is UBL XML?
UBL stands for Universal Business Language.
In short, it is a worldwide standard blueprint for creating electronic business documents, like invoices and purchase orders, using XML code.
Along with CII (Cross Industry Invoice), UBL is one of the two officially approved XML formats allowed by the European Union for electronic invoicing (EN 16931).
UBL vs. CII
It’s the Global Giant: While CII is heavily favored in Germany and France (via ZUGFeRD/Factur-X), UBL is the dominant format across the rest of the globe and the European Peppol network. It is widely used in countries like Belgium, the Netherlands, and across Scandinavia.
It’s just a different dialect: Think of UBL and CII as two different languages saying the exact same thing. A UBL invoice and a CII invoice contain the same business information (tax amounts, line items, buyer details), but the data tags are written differently.
Equally Compliant: Under EU law, public administrations must be able to accept both UBL and CII format invoices. One is not legally "better" than the other.