Tkabber is a GPL instant messaging client for the XMPP protocol which uses the Tk toolkit for the GUI. ...more

AIM is a instat messenger application. ...more

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

Finch is a console-based IM program that lets you sign on to AIM, Jabber, MSN, Yahoo!, and other IM networks. It runs on Unixes. It uses GLib and ncurses. ...more

Blink is the best real-time communications client using the SIP protocol. ...more

Tencent QQ (QQ) is an instant messaging software service. ...more

Otr.to is a browser based chat client. ...more

Icedove is an unbranded Thunderbird mail client suitable for free distribution. ...more

X-Chat 2 for Windows is an unofficial open-source GPL X-Chat (UNIX IRC client) build for Windows. ...more

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

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

ChatSecure is a messaging application for iOS which allows OTR and OMEMO encryption for the XMPP protocol. ...more

Ekiga (GnomeMeeting) is a VoIP and video conferencing application for GNOME and Microsoft Windows. ...more

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

Kopete is a multi-protocol, free software instant messaging client released as part of the KDE Software Compilation. Although it can run in numerous environments, it was designed for and integrates with the KDE Plasma Workspaces. ...more

Psi is a free instant messaging application designed for the XMPP network (including Google Talk). Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X. ...more

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

Nimbuzz is a proprietary cross-platform instant messaging aggregator for smartphones, tablets and personal computers developed by Nimbuzz B.V. Nimbuzz has 150 million users in 200 countries. ...more

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

Digsby provides you with IM, email and Social networks in one easy to use application. ...more

Trillian is a proprietary multiprotocol instant messaging application. ...more

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

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