The XMPP protocol includes a base protocol and many optional extensions typically documented as "XEP'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	XEP #	Description
Private Data	XEP-0049	Manages private data.
XHTML Messages	XEP-0071	Allows send and receiving formatted messages using XHTML.
Message Events	JEP-0022	Requests and responds to message events.
Data Forms	JEP-0004	Allows to gather data using Forms.
Multi User Chat	JEP-0045	Allows configuration of, participation in, and administration of individual text-based conference rooms.
Roster Item Exchange	XEP-0093	Allows roster data to be shared between users.
Time Exchange	XEP-0090	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.
Service Discovery	XEP-0030	Allows to discover services in XMPP entities.
File Transfer	XEP-0096	Transfer files between two users over XMPP.