This practical book provides everything you need to know about the Extensible Messaging and Presence Protocol (XMPP) -- the open technology for real-time communication used in instant messaging, Voice over IP, real-time collaboration, social networking, microblogging, lightweight middleware, cloud computing, and more. XMPP: The Definitive Guide walks you through the thought processes and design decisions involved in building a complete XMPP-enabled application, and adding real-time interfaces to existing applications.