The following tables compare general and technical information for a number of instant messaging clients. Please see the individual products' articles for further information. This article is not all-inclusive or necessarily up-to-date. External links lead to extensions that add a feature to a client.

General information

Basic general information about the real time communication services: creator/company, license/price, amongst others.

Operating system support

The operating systems the clients can run on without emulation or compatibility layers.

Note 1:]] Not a dedicated Mac OS X but a POSIX application: Will need an X server and additional libraries installed, and will not look like a native Mac OS X application.

Note 2: Requires ANSI terminal. See e.g. Windows ANSI driver problem on how to load ANSI.SYS.

Note 3: MSN Web Messenger can be used with a compatible browser and valid Microsoft Passport Network account.

Note 4: Numerous talk/ytalk clients exist for Win32; others are available under the Cygwin environment.

Note 5: Only available in the upcoming version OpenWengo-ng already available through Subversion.

Note 6: Generally only available as source, not as a ready-to-install binary.

Note 7: Client will only work on Mac OS X within a Unix terminal session (Terminal.app, Xterm, iTerm, or similar.)

Note 8: It is called Messenger for Mac, currently version 7.

Features

Information on what features each of the clients support.

Note 1: Plug-in system to add/expand the default features for the application, or protocol. Such as (but not limited to) Trillian chat client - Plugins.

Note 2: Third party add-ons which are usually not approved by the author of the application and are usually standalone. Such as (but not limited to) AOL Instant messenger - Third-party add-ons.

Note 3: Using third party add-on software. Consult the client's page for details.

Note 4: Proprietary; compatible only to itself.

Note 5: ICQ: SSL-encrypted direct connections; compatible between climm, [[licq and Sim-IM.

Note 6: Any protocol: GPG-encrypted messages.

Note 7: Blowfish-encrypted direct connection; compatible only to itself.

Note 8: Newer version Pidgin: Pidgin-encryption plugin, older version Gaim: Gaim-encryption plugin, available at pidgin-encrypt.sf.net. This plugin is compatible with Pidgin/Gaim clients only.

Note 9: Compatible with all Jabber clients implementing JEP-0027 (standard Jabber encryption).