XIFF is an LGPL API for XMPP, the IM protocol that Jabber and Google Talk are based on.

XIFF is highly extensible, and can be used to build a variety of multi-user and presence-based applications that use an XMPP server. Possible applications range from instant messengers to multiplayer games to shared whiteboarding applications to chat rooms.

XIFF can be downloaded from Jive Software's open source repository. The latest version is Beta 4.

Currently, XIFF only officially supports ActionScript 2.0, with an ActionScript 3.0 and Flex 2 compatible version under development (and available for testing from the Subversion repository).

Documenation is included with the API in Beta 3, and seems to be missing in Beta 4. It will be re-included in the upcoming AS3 version.