Open Source

Adium is an Open source multi-protocol instant messaging client for Mac OS X, supports MSN, Jabber, Yahoo! and other networks.

Trillian

Freemium

Trillian is a proprietary multiprotocol instant messaging application.

Psi

Open Source

Psi is a free instant messaging application designed for the XMPP network (including Google Talk). Fast and lightweight, Psi is fully open-source and compatib…

Ring

Open Source

Ring (SFLphone) is an open-source SIP-compatible softphone and instant messenger for Linux, Microsoft Windows, OS X and Android.

Quassel IRC

Open Source

Quassel IRC, or Quassel, is a graphical, distributed, cross-platform IRC client.

Matrix.org

Open Source

Matrix is an open protocol for real-time communication. It is designed to allow users with accounts at one communications service provider to communicate with…

qutIM

Open Source

qutIM is free and open-source multiprotocol (ICQ, Jabber, Mail.Ru, IRC, VKontakte) instant messenger.

Psi+

Open Source

Psi is a cross-platform powerful XMPP/Jabber client (Qt, C++) designed for the Jabber power users. Psi+ is a development branch of Psi IM XMPP/Jabber client.

Coccinella

Open Source

Coccinella is a free and open-source cross-platform client for the XMPP/Jabber-instant messaging-protocol.

Dialog Messenger

Free Personal

Dialog Messenger is a handy and feature-rich enterprise multi-device messenger available for server or cloud.

YakYak

Open Source

YakYak is a desktop chat client for Google Hangouts.

Tox

Open Source

Tox is a peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption.

Jitsi

Open Source

Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application.

Kopete

Open Source

Kopete is a multi-protocol, free software instant messaging client released as part of the KDE Software Compilation. Although it can run in numerous environme…

ICQ

Free

ICQ is an open source instant messaging software.

Instantbird

Open Source

Instantbird is a cross-platform instant messaging client based on Mozillas XULRunner and the open source library libpurple used in Pidgin.

Spark

Open Source

Apache Spark is an open-source cluster-computing framework.

WeeChat

Open Source

WeeChat is a free and open-source Internet Relay Chat client, which is designed to be light and fast.

Kadu

Open Source

Kadu is a free and open source multi-platform instant messaging client that supports Gadu-Gadu, XMPP IM networks and other services based on XMPP like Google …