A universal instant messaging (IM) program
See https://pidgin.im/about/ for more information. Pidgin is an instant messaging program which lets you log in to accounts on multiple chat networks simultaneously. It runs on Windows, Linux, and other UNIX operating systems. Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, MXit, Novell GroupWise Messenger, Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. It is written in C and makes heavy use of GLib and GTK+. Finch is a command line instant messaging program. It also lets you log in to accounts on multiple chat network simultaneously, and it is compatible with the same chat networks as Pidgin. It is written in C and makes heavy use of GLib and ncurses.
Psi IM — Qt-based XMPP/Jabber client
Psi aims to be a feature-rich Jabber/XMPP client for novice and experienced Jabber users. There are builds available for MS Windows, GNU/Linux and macOS.
Psi+ Project — Development branch of Psi IM XMPP/Jabber client
Psi is a cross-platform powerful XMPP/Jabber client (Qt, C++) designed for the Jabber power users. Psi+ is a development branch of Psi IM XMPP/Jabber client. Project Purpose: collection, refinement and writing new patches for transfer them to Psi upstream developers.
A multi-protocol instant messaging app for Mac OS X
Adium is an Open Source, multi-protocol instant messaging application for Mac OS X. Adium supports AIM, ICQ, Jabber, MSN, Yahoo!, Google Talk, Bonjour, Gadu-Gadu, Novell Groupwise, SIP/SIMPLE (Text), and Lotus Sametime. Additionally, it supports all of these applications at once so, even if you have multiple IM accounts, you don't have to log into each account separately.
This is an unofficial native port of Pidgin to Mac OS X. It uses native GTK+ (www.gtk-osx.org) which provides better integration and does not require X11. It also comes with more plugins out of the box, including OTR.
A fork of pidgin which aims to provide minor features that have not been addressed by the pidgin development team (including manual textbox resizing). See funpidgin.sf.net for details.
climm is a portable, small, yet powerful console based, fully internationalized instant messaging client supporting the current v8 ICQ protocol and XMPP.
FireFloo Communicator is a beautiful and slim XMPP & Echo chat client.
FireFloo is an Instant Messaging Communicator combining the open XMPP standard (Jabber, GMail Chat etc.) with the Echo Protocol for secured Chat and Messaging.
The goal of this project is to implement something that allows you to gain access on a remote machine through the XMPP protocol (you need just a Google account!) in a secure and trusted way.
JabberSparrow is a jabber chat client which can expresses user's typing pressure and keystroke. If you type strongly, the words becomes bigger. If you type fast, the words becomes light.
A plugin for Adium to display youtube videos inside the chat window.
wxJabber is an XMPP/Jabber cross-platform client created with wxWidgets.