RESTEasy is a JBoss project that provides various frameworks to help you build RESTful Web Services and RESTful Java applications. It is a fully certified and portable implementation of the JAX-RS specification. JAX-RS is a new JCP specification that provides a Java API for RESTful Web Services over the HTTP protocol.

RESTEasy can run in any Servlet container, but tighter integration with the JBoss Application Server is also available to make the user experience nicer in that environment. While JAX-RS is only a server-side specification, RESTEasy has innovated to bring JAX-RS to the client through the RESTEasy JAX-RS Client Framework. This client-side framework allows you to map outgoing HTTP requests to remote servers using JAX-RS annotations and interface proxies.