The XMPP protocol includes a base protocol and many optional extensions typically documented as "JEP's". Smack provides the org.jivesoftware.smack package for the core XMPP protocol, and the org.jivesoftware.smackx package for many of the protocol extensions.

This manual provides details about each of the "smackx" extensions, including what it is, how to use it, and some simple example code.

Name	JEP #	Description
Private Data	JEP-49	Manages private data.
XHTML Messages	JEP-71	Allows send and receiving formatted messages using XHTML.
Message Events	JEP-22	Requests and responds to message events.
Roster Item Exchange	JEP-93	Allows roster data to be shared between users.
Time Exchange	JEP-90	Allows local time information to be shared between users.
Group Chat Invitations	N/A	Send invitations to other users to join a group chat room.