Psi IM — Qt-based XMPP client
Psi is cross-platform powerful XMPP client designed for experienced users. There are builds available for MS Windows, GNU/Linux and macOS.
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.
Audible Alerts is a Pidgin (libpurple) plugin to produce notification of an IM audibly. It uses eSpeak, a text-to-speech program, to call out the name of the buddy who IMs you. You can download eSpeak from www.sourceforge.net/projects/espeak
PHP Jabber Bot open source. Minimal requirements: PHP > 5[CURL, ICONV, SOCKETS opened 5222 port], MySQL Included many plugins: google, horo, news, translate and more...
It is an instant messaging client. Crony IM has support for some commonly used instant messaging protocols, allowing the user to log into various different services from one application. like LAN, GTalk, Yahoo, Facebook.
A cross-platform multi-service chat and instant messaging GUI client in C++/Qt.
The desktop application for Ribe - A Zimbabwean, African solution to FREE Chat & Messaging
JGGAPi is java implementation of Gadu-Gadu protocol. Gadu-Gadu is a IM system very popular in Poland based on proprietary protocol. The implementation is based on specification of Gadu-Gadu protocol gathered during implementation of EKG application.
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.
Froggie is an easy yet powerful Jabber multiplatform client. Jabber is a powerful open source instant messaging system.
Miranda IM in Polish
ChatCaptain aims to be an alternative to the chat clients not only available on Linux, but also an alternative to the non-free(and free alike) chat clients available on Windows.
imEcourse is a course electing system for college students.It bases on IM.Including executable application IM and web-IM. To use IM to elect course?Of course!
XMPP client for chating
Engroup is the web enterprise groupware promotes various collaboration methods plus adding company business management modules. Features are included: CRM, HRM, Document Management, Project Management, Chat, Wiki, Forum, News, Todo.
climm is a portable, small, yet powerful console based, fully internationalized instant messaging client supporting the current v8 ICQ protocol and XMPP.