There are many instant messaging (IM) clients available for Linux; here are my observations on those that I’ve come across.
When trying IM clients, features I look for include:
- Multiprotocol: Able to connect to all the protocols you need using a single IM client
- Voice and video support
- Capable of running on old, slow hardware, and not tied to overweight dependencies
- Have a large, helpful user community
- Be open source (of course!) and be available in the package managers of major distributions
- Broad selection of plugins
- Encryption available, preferably in a form that does not require the other party to use the same client as you (which I shall call “client agnostic encryption” below)
aMSN: WLM protocol; consciously clones the UI of Windows Live Messenger. Multiplatform. Full featured; supports voice and video. Often criticized as bloated.
CenterIM: Text (ncurses), multiprotocol. No voice or video. Probably the lightest IM client available and my choice for lightweight or underpowered boxes. Simple and clean.
Emesene: WLM protocol. GTK. Multiplatform. Full featured; supports voice and video. Many consider it best of breed of the WLM clients.
Empathy: Gnome/GTK client. Multiprotocol. Supports voice and video. Drags in all of Gnome as a dependency.
Gajim: GTK, multiplatform. XMPP protocol. Supports voice and video.
Gyachi: Yahoo protocol. Supports voice and video. The version I tried was unstable.
Kopete: KDE/QT client. Multiprotocol and multiplatform. Stable, easy to set up and use. Supports video but not voice. Many plugins, including client agnostic encryption. My choice for KDE boxes, but not if IRC support is needed: the IRC plugin is from a third party, is in beta, and hasn’t been updated since 2009.
Pidgin: GTK. Multiprotocol. Lightweight, simple, clean, and a pleasure to use. Many plugins, including client agnostic encryption. Does IRC well. Voice and video are limited to XMPP on Linux. My all-round favorite.
Psi: QT. XMPP protocol.
Some softphones are also IM clients.