Instant messaging clients that use GTK

graphical multi-protocol instant messaging client

XChat (originally styled X-Chat) is an Internet Relay Chat client. It has a tabbed document interface or tree interface, support for multiple servers, and numerous configuration options.

open source instant messaging and VoIP client

Ekiga (formerly called GnomeMeeting) was a VoIP and video conferencing application for GNOME and Microsoft Windows. It was distributed as free software under the terms of the GNU GPL-2.0-or-later. It was the default VoIP client in Ubuntu until October 2009, when it was replaced by Empathy. Ekiga supports both the SIP and H.323 (based on OPAL) protocols and is fully interoperable with any other SIP compliant application and with Microsoft NetMeeting. It supports many high-quality audio and video codecs.

distributed protocol for telephony and instant messaging

Gajim is an instant messaging client for the XMPP protocol which uses the GTK toolkit. The name Gajim is a recursive acronym for "Gajim's a jabber instant messenger". Gajim runs on Linux, BSD, macOS, and Microsoft Windows. Released under the GPL-3.0-only license, Gajim is free software. A 2009 round-up of similar software on Tom's Hardware found version 0.12.1 "the lightest and fastest jabber IM client".

distributed open multimedia communications platform

HexChat is a discontinued Internet Relay Chat client and is a fork of XChat. It has a choice of a tabbed document interface or tree interface, support for multiple servers, and numerous configuration options. Both command-line and graphical versions are available.

Smuxi is a cross-platform IRC client for the GNOME desktop inspired by Irssi. It pioneered the concept of separating the frontend client from the backend engine which manages connections to IRC servers inside a single graphical application.

messaging and collaboration software by GNOME based on the Matrix protocol