E-invoicing, explained clearly — compliance rules for the teams who have to meet them, and integration guides for the developers who build them.
Plain-English explainers on the German and European e-invoicing rules your invoices have to meet — what XRechnung, EN 16931, and country mandates actually require.
European e-invoicing mandates differ by country but share the EN 16931 data model. This 2026 compliance map covers the German XRechnung B2G and B2B mandate, the French Factur-X rollout, Italy, Spain, and Peppol delivery so you know which format each recipient requires.
EN 16931 defines what a compliant European e-invoice must contain. This guide covers the building blocks of the standard, what it leaves to country customizations, and how it connects to XRechnung and ZUGFeRD.
XRechnung is the German public-sector e-invoice format. This guide explains what it is, who needs it, how it relates to EN 16931 and ZUGFeRD, and what a compliant invoice must contain — without the jargon.
Step-by-step developer walkthroughs for generating and validating e-invoices with the InvoiceSpec API — request payloads, code samples, and edge cases.
A developer guide to validating a XRechnung XML file against the KoSIT XSD and Schematron rules. Covers the validate endpoint, the structured validation report, issue severities, and the most common rule violations.
A step-by-step developer walkthrough for generating a ZUGFeRD PDF/A-3 with embedded CII XML from one API call. Covers the ZUGFeRD profiles, the request payload, PDF language selection, validation, and error handling.
A step-by-step developer walkthrough for generating compliant XRechnung CII XML with one API call. Covers the request payload, AUTO mode totals, syntax selection, validation, and error handling.
Deep dives into the formats and syntaxes behind e-invoicing — CII vs UBL, XRechnung vs ZUGFeRD, and how the standards map to each other.
CII and UBL are the two XML syntaxes EN 16931 allows. This comparison covers the structure, namespaces, where each is used, and how to choose between them for XRechnung, ZUGFeRD, and Peppol delivery.
MINIMUM, BASIC, COMFORT, and EXTENDED are ZUGFeRD profiles, not XRechnung levels. This guide explains the ZUGFeRD profile ladder, where the XRECHNUNG profile fits, and how to choose the right level for your recipient.
XRechnung and ZUGFeRD both build on EN 16931 but deliver invoices differently. This comparison covers the container formats, profiles, and when to use each so you can pick the right one for your recipient.