ZUGFeRD, XRechnung, Factur-X, ebInterface: the e-invoice formats explained

Anyone encountering e-invoicing for the first time soon runs into a series of names: XRechnung, ZUGFeRD, Factur-X, ebInterface, Peppol BIS. The variety looks confusing, but it falls into place once the shared foundation is clear.

The foundation: EN 16931

Almost all relevant formats build on the same European standard, EN 16931. This standard is not a file format but a semantic data model. It defines what information an invoice must contain and how those fields (the so-called BT and BG elements) are named and related to one another, complemented by business rules (BR rules) governing, for example, the calculation of totals.

The individual formats are different technical expressions of precisely this model. That is also why invoices can be converted between formats: beneath the respective syntax lies the same data model.

Two designs: purely structured and hybrid

The key distinction runs between two designs.

Purely structured formats consist solely of XML, that is, raw data with no fixed visual representation. This is ideal for machine processing but barely legible to the human eye without assistance. XRechnung is the best-known example.

Hybrid formats combine both worlds in a single file. ZUGFeRD and the largely identical French Factur-X embed the structured XML data within a PDF/A-3 document. What is visible is an ordinary, readable PDF invoice, while the same data is carried along in machine-readable form in the background. This makes hybrid formats convenient, because they work for both sides, for manual review as well as automated processing.

The formats in detail

XRechnung is the core standard for invoices to German public authorities, mandatory there since November 2020. It is a pure XML format that can be based on either of two syntaxes (UBL or CII).

ZUGFeRD and Factur-X are the hybrid formats of PDF plus embedded XML. The EN-16931-compliant profiles are those from ZUGFeRD version 2.0.1 onward, in particular the EN 16931 (Comfort), Extended, and XRechnung profiles. Older or reduced profiles (such as MINIMUM or BASIC WL) do not fully meet the standard. These formats are widely used in the B2B sector across Germany and France.

ebInterface is the Austrian XML standard, developed and maintained by AUSTRIAPRO. Since version 5.0 the format has been built on the EN 16931 data model; the current version 6.1 is EN-16931-compliant. For invoices to the Austrian federal government, ebInterface (alongside Peppol BIS) is the relevant format.

Peppol BIS 3.0 is, strictly speaking, not a national format in its own right but a specification based on EN 16931, intended primarily for standardised exchange across the pan-European Peppol network.

Why a tool helps

Because these formats coexist and a different one is required depending on the recipient, a tool that recognises, checks, and converts between them is useful. That is exactly what milchrechnung.at was built for: drag in a file, and the tool detects the format, validates it against the official rule sets, displays the contents in readable form, and converts to another format when needed. The individual technical terms are also explained in the glossary.