Dopo che sono state rilasciate le specifiche del progetto Liberty, ecco una prima implementazione open source, segnalata dalla sezione per sviluppatori del sito Sun dedicato a Java. Interoperability Prototype for Liberty is the first open-source implementation of the Liberty Alliance Version 1.0 specification based on JavaTM technology. IPL is designed to help developers learn how the project Liberty Alliance Version 1.0 specification can be implemented. Written for the Java 2 platform, IPL provides the foundation for building liberty into applications and testing interoperability between liberty compliant solutions such as the SunTM ONE Identity Server version 6.0.