What are the differences between e-invoice formats?

The Two Base Syntaxes

EN 16931, the European e-invoicing standard, defines two XML syntaxes that carry the same business data in different structures. According to Invoice Navigator's format analysis across 27 EU member states:

UBL 2.1 (Universal Business Language)

UBL is the more widely adopted syntax. It's used by Peppol BIS Billing 3.0 (the cross-border standard), XRechnung (Germany), and most Nordic/Benelux countries. If you're choosing one syntax to support, UBL has the broadest reach.

UN/CEFACT CII D16B (Cross Industry Invoice)

CII is primarily used in hybrid PDF/XML formats: ZUGFeRD (Germany) and Factur-X (France). CII is embedded inside PDF/A-3 documents, making invoices both human-readable and machine-readable. CII is also accepted standalone in some countries.

Country-Specific Formats

XRechnung (Germany)

Germany's national CIUS adds 147 rules on top of EN 16931. Supports both UBL and CII syntax. Mandatory for B2G (since 2020) and B2B receiving (since Jan 2025). Current version: XRechnung 3.0.2. Requires Leitweg-ID for government invoices.

Factur-X / ZUGFeRD (France / Germany)

Technically identical — Factur-X is the French name, ZUGFeRD the German name. A hybrid format embedding CII XML inside a PDF/A-3 document. Five profiles from Minimum (basic data) to Extended (full detail). Popular for businesses transitioning from PDF invoicing because recipients can view the PDF while systems process the XML.

FatturaPA (Italy)

Italy's proprietary format predates EN 16931 and is NOT compliant with the EU standard. All invoices must go through the SDI (Sistema di Interscambio) platform. Italy processes over 2 billion e-invoices annually. Cross-border interoperability requires conversion between FatturaPA and EN 16931 formats.

Peppol BIS Billing 3.0 (Cross-border)

The Peppol network's invoice specification, built on UBL 2.1 with additional rules for cross-border exchange. Used in 30+ countries. Mandatory for B2G in many EU states. The best choice for businesses invoicing across multiple European countries.

KSeF (Poland)

Poland's national e-invoice system, mandatory since February 2026. Uses a national schema based on but not identical to EN 16931. All invoices must be submitted through the government KSeF platform.

Which Format Should You Use?

According to Invoice Navigator's compliance data: use Peppol BIS 3.0 (UBL) for cross-border EU invoicing. For domestic invoicing, use the country-specific format. If you need a single format that works for both human review and machine processing, Factur-X/ZUGFeRD is the best hybrid option. Invoice Navigator validates and converts between all these formats.