Facturexa Validator

ZUGFeRD validator for .NET: reliably validate incoming e-invoices

The Validator extracts the embedded XML from an invoice PDF, checks the PDF container (PDF/A-3 & Factur-X) and validates the XML against the official rule sets – all the way to the official Schematron validation of Factur-X/ZUGFeRD and KoSIT XRechnung. Validation runs entirely offline inside your application – all rule sets ship with the package, no invoice ever leaves your system.

Try without obligation for 30 days Try the live demo Documentation
  • .NET Framework 4.8
  • .NET 8
  • .NET 10
  • ZUGFeRD 2.5.2 / Factur-X 1.09.2
  • XRechnung 3.0 (CII & UBL)
Facturexa.ZugferdValidator
dotnet add package Facturexa.ZugferdValidator
Install-Package Facturexa.ZugferdValidator
1

PDF container

PDF/A-3 conformance, file naming convention, XMP metadata and the Factur-X embedding of the XML are checked – in line with the official ZUGFeRD validation tool.

2

Official XML schema

The Validator first checks CII invoices against the official XML schema: ZUGFeRD/Factur-X against the schema of the respective profile (Factur-X 1.09.2), which only allows that profile’s elements, and XRechnung against CII D16B like the KoSIT validator. This also catches structural errors the Schematron does not see – such as a wrong element order or an element not allowed in the profile.

3

Official Schematron

The official Schematron then checks the business rules (Factur-X/ZUGFeRD or KoSIT XRechnung, via Saxon/XSLT 2.0) – the same rule sets your invoice recipients use. An invoice is only valid if both checks pass.

Fully offline

The Validator needs no internet connection at runtime and calls no external service.

  • Data protection: invoices are validated solely inside your application – nothing is sent to third parties.
  • No internet required: works in isolated networks and on servers without internet access.
  • Independent: no outages or limits of an online validation service; the license check runs locally too.

Coverage

The Validator covers all common profiles – for XRechnung both the CII and the UBL syntax.

Profile Description Validator Creator
MINIMUM Header data only, not a valid e-invoice format on its own ✔ Yes ✔ Yes
BASIC WL Header data without invoice lines ✔ Yes ✔ Yes
BASIC Core information including invoice lines ✔ Yes ✔ Yes
EN 16931 / COMFORT European core standard – valid e-invoice format ✔ Yes ✔ Yes
EXTENDED Extended data set; from ZUGFeRD 2.5.2 including sub-lines, kits & bundles ✔ Yes ✔ Yes
XRechnung 3.0 (CIUS) German B2G core variant, two-stage EN 16931 + CIUS ✔ Yes (CII + UBL) ✔ Yes (CII)
UBL generation Output XRechnung as UBL instead of CII n/a (already validated) Roadmap

Integration made simple

A single call is enough: pass the PDF and the Validator checks the PDF container, the XML schema and the official Schematron. The example below mirrors the actual flow used by the live demo on this site.

C# – Validator.cs
using Facturexa.ZugferdValidator;

// Once at application startup.
ZugferdValidatorLicense.RegisterLicense("…");

// PDF container (PDF/A-3 & Factur-X), XML schema and official Schematron in one call.
var result = ZugferdValidator.Validate("invoice.pdf", "INV-2026-0001");

if (result.IsPdfValid == false)
    Console.WriteLine("PDF container not compliant");

if (!result.IsValid)
{
    foreach (var error in result.Errors)
        Console.WriteLine($"{error.Stage}: {error}"); // e.g. "Schematron: BR-CO-15 (BT-112): ..."
}

Validator and Creator in one license

Validate and create e-invoices – for incoming and outgoing invoices alike. The Reader is free.

from 500 EUR net / year
companies outside Germany receive a quote on request
Try without obligation for 30 days View license tiers