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

phoss SMP - a Peppol and OASIS BDXR SMP Server, CEF eDelivery compliant

Java library with shared Peppol components - identifier handling, codelists, SBDH handler, SMP Client, SML Client, MLR handler, MLS handler

Oxalis-NG (Oxalis - Next Generation) - Open-Source implementation of OpenPeppol AS4 profile

The official Peppol Directory software