Interactive reference for EN 16931 e-invoice fields. Search business terms, see UBL 2.1 and CII XML paths side by side. For developers building e-invoicing integrations.
Send and receive EN 16931-compliant invoices via our REST API. No XML assembly required.
EN 16931 is the European standard for the semantic data model of an electronic invoice. It was developed by CEN (European Committee for Standardization) and adopted by the EU to ensure interoperability across all member states. The standard defines business terms (BT) and business groups (BG) that describe the meaning of each invoice field, independent of any specific XML format.
EN 16931 is required by EU Directive 2014/55/EU for public procurement invoicing. It forms the foundation of the Belgian e-invoicing mandate (January 2026) and the upcoming EU ViDA regulation for cross-border B2B e-invoicing.
Universal Business Language. Uses cbc/cac namespace prefixes. The syntax chosen by Peppol BIS 3.0 and used across most of Europe for Peppol invoicing. Paths start with /Invoice/.
Cross Industry Invoice. Uses rsm/ram namespace prefixes. The syntax used by ZUGFeRD (Germany), Factur-X (France), and XRechnung (supports both). Paths start with /rsm:CrossIndustryInvoice/.
Both syntaxes express the same EN 16931 semantic model. Every business term maps to exactly one XML element in each syntax. This tool shows you both paths side by side, so you can easily translate between UBL and CII or build support for both formats.
Type any BT ID (e.g. "BT-1"), field name (e.g. "invoice number"), or even an XML element name (e.g. "PayableAmount") to find the matching term.
Use the filters to narrow down to a specific business group (e.g. BG-4 Seller) or data type (e.g. Amount, Code). Toggle between UBL-only, CII-only, or both paths.
Click any row to expand it and see the full description, data type, and cardinality. Use the copy button to copy the exact XML path for your code.
The EN 16931 semantic model is the foundation of every major e-invoicing standard in Europe. Here is how different standards use it:
Uses UBL 2.1 syntax. The standard for cross-border B2B e-invoicing via the Peppol network. Mandatory in Belgium since January 2026 for B2B invoices.
Supports both UBL 2.1 and CII syntaxes. Required for invoicing to German public authorities. Adds national rules (CIUS) on top of EN 16931.
Uses CII syntax embedded in PDF/A-3 files. A hybrid format that combines a human-readable PDF with machine-readable XML. Popular in Germany, France, and growing across Europe.
Uses UBL 2.1 syntax. The Dutch CIUS (Core Invoice Usage Specification) adds country-specific rules for invoicing in the Netherlands.
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EN 16931 defines the semantic data model: what information an e-invoice must contain (business terms like "Invoice number", "Seller name", etc.). UBL 2.1 is one of two XML syntaxes used to express that model in a machine-readable format. CII is the other. Think of EN 16931 as the "what" and UBL/CII as the "how".
Peppol BIS Billing 3.0 uses UBL 2.1 syntax exclusively. If you are building a Peppol integration, you only need the UBL column in this reference. CII is used by ZUGFeRD, Factur-X, and optionally by XRechnung.
Cardinality defines how many times a business term can or must appear. "1..1" means mandatory (exactly once). "0..1" means optional (zero or one time). "0..n" means optional and repeatable (zero or more times). Some terms that are optional in EN 16931 may be mandatory in specific CIUS implementations like Peppol BIS.
This reference covers the most commonly used business terms and groups from EN 16931. It includes all header-level fields, seller and buyer information, payment instructions, document totals, VAT breakdown, invoice lines, price details, and item information. Some rarely used groups (like preceding invoice reference or additional supporting documents) are not included for clarity.
This reference shows the XML path mappings, which is the first step in building a UBL-to-CII or CII-to-UBL converter. However, format conversion also requires handling differences in date formats, namespace declarations, element ordering, and attribute handling. Use this as a field-level mapping reference and consult the official EN 16931 syntax binding documents for the full conversion rules.
Since January 2026, all B2B invoices in Belgium must be sent electronically via the Peppol network. Peppol uses UBL 2.1 following the EN 16931 semantic model. This means every Belgian B2B invoice must contain the mandatory EN 16931 business terms mapped to UBL 2.1 XML elements.
Detailed breakdown of every field in a Peppol BIS 3.0 UBL invoice.
Plain-language guide to XML invoicing with real examples.
Upload a UBL XML file and see it rendered as a readable invoice.
View and extract CII XML data from ZUGFeRD and Factur-X PDF invoices.
Need to send EN 16931-compliant invoices? Create a free account or explore the Peppol API.
Check if a company is on Peppol with our Peppol Radar. View XRechnung invoices with the XRechnung Viewer.
