Avalara E-Invoicing

Judgement

What it is

Integration

What it does

Connects ERPs to government e-invoicing and real-time reporting systems in many countries, converting and submitting invoices in each mandated format.

Adopt it when

A multinational must comply with e-invoicing mandates in several countries and already uses Avalara for tax.

Watch out

Costs scale with volume and countries, and you depend on Avalara keeping pace with each mandate.

Ready for

Production-ready

Runs as

Cloud service

What the license allows

Closed source: you use it under the maker's terms and cannot change or resell the code.

Judged on 2026-11-03 from the maker's description and Wikipedia. The license and age lines are worked out directly.

Open-source alternatives to Avalara E-Invoicing

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
   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
6. 6
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   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
7. 7
   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
8. 8
   Factur-X atgp

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   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
9. 9
   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
10. 10
    Ph-ubl phax

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    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

Other commercial e-invoicing libraries for ZUGFeRD, Factur-X, XRechnung and Peppol

1. 1
   Pagero Pagero

   Discover e-invoicing, tax, legal and regulatory compliance solutions from Thomson Reuters, helping organisations navigate complexity with confidence.

   Integration Production-ready A company trading across several countries must send and receive structured e-invoices to meet mandates.

   77 readers a month Commercial

Under it

Every program, Avalara E-Invoicing included, runs on a microchip.

How compilers were built, back to punched paper tape