A free API for generating invoice PDFs and e-Invoices.
Validation artefacts for the European eInvoicing standard EN 16931
Library for reading and creating European-compliant electronic invoices ...
Java library for reading and writing UBL 2.0, 2.1, 2.2, 2.3 and 2.4 (CS0...
C# / .NET / XML library for working with OASIS UBL 2.0/2.1 documents
A modern object-oriented PHP library to create valid UBL and Peppol BIS ...
eForms is the notification standard for public procurement procedures in...
Validates XML documents with XML Schema and Schematron