Glossary
A short, plain-language reference for the e-invoicing standards and terms the API works with. If a word in the docs is unfamiliar, it is probably explained here.
Standards and formats
| Term | Definition |
|---|---|
| EN 16931 | The European standard that defines the semantic data model of an electronic invoice: what fields exist and what they mean. Every format below is a way of expressing an EN 16931 invoice. |
| CII | Cross Industry Invoice, a UN/CEFACT XML syntax for invoices. It is the XML carried inside Factur-X and ZUGFeRD files. |
| UBL | Universal Business Language, the OASIS XML syntax for invoices. The other EN 16931 syntax, used widely on the Peppol network. |
| Factur-X | A Franco-German hybrid invoice: a PDF/A-3 document with an EN 16931 CII XML file embedded inside it. |
| ZUGFeRD | The German name for the same hybrid standard as Factur-X. ZUGFeRD 2.x and Factur-X are technically identical. |
| XRechnung | The German specification for invoicing public-sector buyers (B2G). A pure XML invoice, in either CII or UBL syntax, with extra German-specific rules. |
| Peppol BIS | The Peppol Business Interoperability Specification, a UBL-based profile used to exchange invoices over the Peppol network across borders. |
| PDF/A-3 | An ISO archival PDF format that allows other files to be embedded inside it. It is what lets a hybrid invoice carry its XML. |
Terms and concepts
| Term | Definition |
|---|---|
| BT (Business Term) | A single piece of invoice data. For example, BT-1 is the invoice number and BT-5 is the currency. |
| BG (Business Group) | A group of related Business Terms. For example, BG-4 groups all the seller fields together. |
| BR (Business Rule) | A validation rule from EN 16931. For example, BR-06 requires that an invoice contain the seller name. A failed BR is what produces a validation error. |
| CIUS | Core Invoice Usage Specification, a national or sector-specific tightening of EN 16931. XRechnung and Peppol BIS are both a CIUS. |
| Schematron | The rule language the EN 16931 business rules are written in. The validation endpoints run Schematron against your invoice. |
| Profile | A Factur-X / ZUGFeRD conformance level (MINIMUM, BASIC WL, BASIC, EN 16931, EXTENDED) that determines which fields an invoice is allowed to carry. |
| Hybrid invoice | A single PDF that is both human-readable (the visible page) and machine-readable (the embedded XML). Factur-X and ZUGFeRD are hybrid invoices. |
| Leitweg-ID | The routing identifier a German public-sector buyer issues. It is carried in the buyer reference (BT-10) and is required by XRechnung. |
| Finding | One entry in the errors or warnings array of an API response, describing a single validation issue. See Error Handling. |