Although historically an open-source part of the GlassFish application server, it can also be used in a stand-alone configuration.

Originally available under the CDDL and GPLv2 with classpath exception,[2] it is now available under Eclipse Distribution License [Wikidata] Originally, the Glassfish project developed two semi-independent projects: In June 2007, it was decided to bundle these two components as a single component named Metro.

Codehaus started a comparison[4] which compared Apache Axis 1.x, Axis 2.x, Celtix, Glue, JBossWS, Xfire 1.2 and JAX-WS RI + WSIT (the bundle was not yet named Metro at that time).

[6] Its features include: Supported WS-* Standards[5] Supported Transport protocols include: Metro augments the JAX-WS environment with advanced features such as trusted, end-to-end security; optimized transport (MTOM, Fast Infoset), reliable messaging, and transactional behavior for SOAP web services.

[7] Metro is bundled with numerous application servers such as:[8] The JAXB reference implementation developed for Metro is used in virtually every Java Web Services framework (Apache Axis2, Codehaus XFire, Apache CXF) and Application Servers.