Open-source e-invoicing libraries for ZUGFeRD, Factur-X, XRechnung and Peppol in 2026

All open-source e-invoicing libraries for ZUGFeRD, Factur-X, XRechnung and Peppol, ranked

Complete systems you can adopt 3

1. 1
   Quba-viewer ZUGFeRD

   Quba is a viewer for electronic invoices

   Complete system Usable Someone in accounts receives XML e-invoices and needs to read and check them locally.

   ★ 206 Apache-2.0 Kotlin Active, pushed 10 days ago
2. 2
   OpenXRechnungToolbox jcthiele

   Graphische Benutzeroberfläche für die Visualisierung und Validierung von XRechnung (und anderen EN16931-konformen E-Rechnungen) sowie ein Tool für die Berechnung und Prüfung von Leitweg-IDs. || Engl.: Graphical User Interface for visualization and validation of XRechnung (and other EN16931 compliant e-invoices) as well as tool for Leitweg-ID calculation and validation.

   Complete system Usable A German organisation needs to view and validate XRechnung files locally without programming.

   ★ 64 GPL-3.0 XSLT Quiet, pushed 2 years ago
3. 3
   ZUGFeRD-Manager OpenIndex

   A desktop application, that creates and validates ZUGFeRD invoices.

   Complete system Usable A small German business wants to check or produce ZUGFeRD invoices without uploading them anywhere.

   ★ 39 Apache-2.0 Kotlin Quiet, pushed 17 months ago

Building blocks for your own system 14

1. 1
   Mustangproject ZUGFeRD

   Open Source Java e-Invoicing library, validator and tool (Factur-X/ZUGFeRD, UNCEFACT/CII XRechnung)

   Building block Production-ready A Java application must produce or check German or French e-invoices.

   ★ 483 Apache-2.0 XSLT Active, pushed 17 days ago
2. 2
   ZUGFeRD horstoeko

   ZUGFeRD/XRechnung/Factur-X Library

   Building block Production-ready You maintain a PHP app already using it; new projects should start with its successor, horstoeko/invoicesuite.

   ★ 437 MIT PHP Active, pushed 32 days ago
3. 3
   ZUGFeRD-csharp stephanstapel

   Open source C# e-invoicing library. Enables creating and reading ZUGFeRD invoices.

   Building block Production-ready Only for existing .NET projects that need a short bridge; new work should look elsewhere.

   ★ 395 Apache-2.0 C# Active, pushed 24 days ago
4. 4
   Phase4 phax

   phase4 - AS4 client and server for integration into existing systems. Specific support for Peppol and CEF eDelivery built-in.

   Building block Production-ready You are building a Peppol access point or another AS4 integration in Java.

   ★ 246 Apache-2.0 Java Active, pushed 3 days ago
5. 5
   Python-drafthorse pretix

   Pure-python ZUGFeRD implementation

   Building block Usable A Python application must emit ZUGFeRD invoices and the developer can work from the official specification.

   ★ 182 Apache-2.0 Python Active, pushed 5 days ago
6. 6
   ZATCA SallaApp

   An unofficial package maintained by Salla to help developers to implement ZATCA (Fatoora) QR code easily which required for e-invoicing

   Building block Usable A PHP system selling in Saudi Arabia must generate ZATCA-compliant invoices.

   ★ 168 MIT PHP Active, pushed 21 days ago
7. 7
   Factur-X atgp

   PHP library to manage your Factur-X / ZUGFeRD 2.0 PDF invoices files

   Building block Usable Your PHP system already produces PDF invoices and the XML, and needs to combine them into Factur-X files.

   ★ 154 MIT PHP Active, pushed 3 months ago
8. 8
   UBL Invoice num-num

   A modern object-oriented PHP library to read and create valid UBL and Peppol BIS files

   Building block Usable Your PHP app must send UBL invoices over Peppol, for example in Belgium.

   ★ 142 MIT PHP Active, pushed 13 days ago
9. 9
   Ph-ubl phax

   Java library for reading and writing UBL 2.0, 2.1, 2.2, 2.3, 2.4 and 2.5 documents

   Building block Production-ready A Java system handles UBL invoices, orders or other procurement documents.

   ★ 142 Apache-2.0 Java Active, pushed 7 days ago
10. 10
    XRechnung Visualization itplr-kosit

    XSL transformators for web and pdf rendering of German CIUS XRechnung or EN16931-1:2017 [MIRROR OF GitLab]

    Building block Production-ready Your software must show German e-invoices to people in the standard reference layout.

    ★ 134 Apache-2.0 XSLT Active, pushed 20 days ago
11. 11
    Validator-configuration-xrechnung itplr-kosit

    Configuration for validating documents against the German XRechnung standard using the KoSIT validation tool

    Building block Production-ready You build or test software that sends or receives German e-invoices and need the reference validation rules.

    ★ 119 Apache-2.0 XSLT Active, pushed 7 days ago
12. 12
    ZUGFeRD PHP easybill

    ZUGFeRD PHP SDK (Factur-X, XRechnung)

    Building block Production-ready A PHP invoicing system needs to read or write ZUGFeRD XML and wants a library from an invoicing vendor.

    ★ 103 MIT PHP Active, pushed 12 days ago
13. 13
    Phive phax

    Generic business document validation engine

    Building block Production-ready You build Peppol or e-invoicing software in Java and need standard document validation.

    ★ 77 Apache-2.0 Java Active, pushed 5 days ago
14. 14
    Einvoicing josemmo

    Library for reading and creating European-compliant electronic invoices (EN 16931)

    Building block Usable A PHP application needs to produce Peppol or EN 16931 invoices without a commercial SDK.

    ★ 179 MIT PHP Quiet, pushed 17 months ago

Integrations 1

1. 1
   Eu_einvoice alyf-de

   Create and import e-invoices with ERPNext.

   Integration Usable A business in Germany or France runs ERPNext and must send or receive e-invoices.

   ★ 104 GPL-3.0 Python Active, pushed 3 days ago

Developer tools 1

1. 1
   Xrechnung-testsuite itplr-kosit

   Test instances for the XRechnung Standard, the German Core Invoice Usage Specification of CEN EN16931 [MIRROR of GitLab]

   Developer tool Production-ready You are building an XRechnung implementation and need reference test files.

   ★ 101 Apache-2.0 XSLT Active, pushed 2 months ago

Compared head to head

Also under accounting software

Open-source licenses

• Permissive: 17. Use it anywhere, including in closed products. You keep the copyright notice; Apache-2.0 also grants patent rights.
• Strong copyleft: 2. If you distribute the program or anything built on it, you must release the whole source under the same license.

Languages

PHP 6, XSLT 5, Java 3, Kotlin 2, Python 2 and C# 1.