Ejabberd

ejabberd is an XMPP application server, written mainly in the Erlang programming language. It can run under several Unix-like operating systems such as Mac OS X, GNU/Linux, FreeBSD, NetBSD, OpenBSD and OpenSolaris. Additionally, ejabberd can run under Microsoft Windows, however, a user must stay logged in or always restart the ejabberd service remotely after any logout from the machine. ejabberd stands for Erlang Jabber Daemon (Jabber being a former name for XMPP), and is written in lowercase only, as is common for daemon software.