Skype is an instant messaging and VOIP (Voice Over Internet Protocol) client to communicate with people in a distant place.

Viber Free Messenger and Phone Calls.

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.

Toky is an automation platform.

Pidgin is a free and open-source chat client which supports AIM, Google Talk, ICQ, XMPP protocols.

Wire is a cross-platform, encrypted instant messaging client created by Wire Swiss. It is available for iOS, Android, Linux, Windows, macOS and Web browser cl…

QuteCom (WengoPhone) is a free-software SIP-compliant VoIP client.