appear.in provides one-click video conferences right in your browser without requiring PIN codes or additional software.

Dasher Messenger provids a way to message friends.

Gajim is an instant messaging client for the XMPP protocol which uses the GTK+ toolkit.

IM+ supports simultaneously major IM services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber (and Slack through Jabber), etc.

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

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

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

Empathy is an instant messaging (IM) and voice over IP (VoIP) client which supports text, voice, video, file transfers, and inter-application communication ov…

Hangouts is an instant messaging software developed by Google.

Phoner and PhonerLite are softphone applications for Windows operating systems available as freeware.

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…

Tango is the messaging app with the best video calling. All messages and calls are free.