In this book, we focused primarily on XMPP protocols and the thought processes and design decisions involved in building XMPP applications. There’s a good reason for this: so many XMPP-based software codebases exist that describing XMPP only in terms of a particular server, library, or API might limit your ability to translate what you’ve learned into other codebases. However, we would be remiss if we didn’t describe some of the more popular software projects in the XMPP community. This list is only a snapshot of the (mostly free and open source) software projects that are relatively active at the time of this writing. By the time you read this, it’s possible that some of these projects will have disappeared or at least become obsolete, while new projects will have emerged, so visit http://xmpp.org for up-to-date links to the wealth of XMPP-based software applications.
The following list describes the most popular open source XMPP servers:
This is the server created by SixApart for its LiveJournal deployment, known as LJ Talk. The djabberd codebase is designed to be extremely modular. It is something of a bare-bones implementation without a lot of polish or packaging, so if you use it, be prepared to get your hands dirty. The original developers still contribute to the project, and patches come in on a fairly regular basis. Language: Perl. License: GPL. Website: http://www.danga.com/djabberd/.
The ejabberd project ...