iChat Server is a component of Mac OS X Server from Apple Inc. It was first introduced with the release of version 10.4 of the server software, and was upgraded to version 2 with the release of Mac OS X Server 10.5 in October 2007.
iChat Server was originally based on jabberd 1.4.3 and is named after Apple's iChat online chat client software.
Version 2 of the software is based on jabberd2 2.0s9 and supports server federation, which allows chat clients to talk directly with other systems that support XMPP, such as Google Talk. It also supports server-based chat archiving.