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 client
Psi is cross-platform powerful XMPP client designed for experienced users. There are builds available for MS Windows, GNU/Linux and macOS.
Psi+ Project — development branch of Psi XMPP client
Psi is a cross-platform powerful XMPP client designed for experienced users. Psi+ is a development branch of Psi XMPP client. Project purpose: collection, refinement and writing new patches for transfer them to Psi upstream developers.
climm is a portable, small, yet powerful console based, fully internationalized instant messaging client supporting the current v8 ICQ protocol and XMPP.
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...
flManowar is simple jabber client with boards games support (battleship,checkers and reversi included)
Jabba is a Jabber client wrote in java/
Java IM client with GUI based on JavaFX
This a new instant messenger for unix.
Gamra is a client of MRA chat for linux, by other words - Gamra is an IM client. MRA - Mail.RU Agent, the russian analog of ICQ. In the future, there will be an ICQ suppurt in GAMRA too.
Communication service (voip + chat)
Instant messenger on C for Linux platform
Skysiss.com - IM bots and applications
Skysiss Skype, Jabber, Whatsapp IM bot assistants allow you to send messages to other IM. Replacement for your Weather application, Calculator and many others. Skysiss bots work directly from you favorite IM client.