Free instant messaging clients

privacy-focused encrypted messaging app

graphical multi-protocol instant messaging client

Kopete was 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. Kopete was started because ICQ blocked Licq from their network in 2001. According to the original author, Duncan Mac-Vicar Prett, the name comes from the Chilean Spanish word copete, meaning "a drink with your friends". Kopete has been nominated for multiple awards. The designated successor is KDE Telepathy from the KDE RTCC Initiative.

Jitsi (from , "wires") is a collection of free and open-source multiplatform voice (VoIP), video conferencing and instant messaging applications for the Web platform, Windows, Linux, macOS, iOS, iPadOS, watchOS, and Android. The Jitsi project began with the Jitsi Desktop (previously known as SIP Communicator). With the growth of WebRTC, the project team focus shifted to the Jitsi Videobridge for allowing web-based multi-party video calling. Later the team added Jitsi Meet, a full video conferencing application that includes web, Android, iOS, iPadOS, and watchOS clients. Jitsi also operates me

aMSN was a free Windows Live Messenger clone. aMSN attempted to emulate the look and feel of Windows Live Messenger, and supported many of its features. It had been downloaded approximately 40 million times as of January 2011, making it the 21st most downloaded project on SourceForge.

open source instant messaging and VoIP client

decentralized encrypted chat and collaboration software powered by the Matrix protocol

Ekiga (formerly called GnomeMeeting) was a VoIP and video conferencing application for GNOME and Microsoft Windows. It was distributed as free software under the terms of the GNU GPL-2.0-or-later. It was the default VoIP client in Ubuntu until October 2009, when it was replaced by Empathy. Ekiga supports both the SIP and H.323 (based on OPAL) protocols and is fully interoperable with any other SIP compliant application and with Microsoft NetMeeting. It supports many high-quality audio and video codecs.

instant messenger for Microsoft Windows, free software

Adium is a free and open-source instant messaging client for macOS that supports multiple IM networks, including XMPP (Jabber), IRC and more. In the past, it has also supported AIM, ICQ, Windows Live Messenger and Yahoo! Messenger. Adium is written using macOS's Cocoa API, and it is released under the GNU GPL-2.0-or-later and many other licenses for components that are distributed with Adium.

instant messaging client

distributed protocol for telephony and instant messaging

distributed open multimedia communications platform

Gajim is an instant messaging client for the XMPP protocol which uses the GTK toolkit. The name Gajim is a recursive acronym for "Gajim's a jabber instant messenger". Gajim runs on Linux, BSD, macOS, and Microsoft Windows. Released under the GPL-3.0-only license, Gajim is free software. A 2009 round-up of similar software on Tom's Hardware found version 0.12.1 "the lightest and fastest jabber IM client".

instant messaging client

Retroshare is a free and open-source peer-to-peer communication and file sharing app based on a friend-to-friend network built by GNU Privacy Guard (GPG). Optionally peers may exchange certificates and IP addresses to their friends and vice versa.

QuteCom (previously called WengoPhone) was a free-software SIP-compliant VoIP client developed by the QuteCom (previously OpenWengo) community under the GPL-2.0-or-later license. It allows users to speak to other users of SIP-compliant VoIP software at no cost. It also allows users to call landlines and cell phones, send SMS and make video calls. None of these functions are tied to a particular provider, allowing users to choose among any SIP provider.

Cryptocat is a discontinued open-source desktop application intended to allow encrypted online chatting available for Windows, OS X, and Linux. It uses end-to-end encryption to secure all communications to other Cryptocat users. Users are given the option of independently verifying their buddies' device lists and are notified when a buddy's device list is modified and all updates are verified through the built-in update downloader.

Instantbird is a discontinued cross-platform instant messaging client based on Mozilla's XULRunner and the open-source library libpurple used in Pidgin. Instantbird is free software available under the GNU General Public License. Over 250 add-ons allow user customization of, and addition of, features. On October 18, 2017, Florian Quèze announced that "... we are stopping development of Instantbird as a standalone product."

TextSecure was an encrypted messaging application for Android that was developed from 2010 to 2015. It was a predecessor to Signal and the first application to use the Signal Protocol, which has since been implemented into WhatsApp and other applications. TextSecure used end-to-end encryption to secure the transmission of text messages, group messages, attachments and media messages to other TextSecure users.

encrypted private messenger

Centericq is a text mode menu- and window-driven instant messaging interface that supports the ICQ, Yahoo!, AIM, MSN, IRC, XMPP, LiveJournal, and Gadu-Gadu protocols.

BitlBee is a cross-platform IRC instant messaging gateway, licensed under the terms of the GNU General Public License.

real-time communication software framework

WASTE is a peer-to-peer and friend-to-friend protocol and software application developed by Justin Frankel at Nullsoft in 2003 that features instant messaging, chat rooms, and file browsing/sharing capabilities. The name WASTE is a reference to Thomas Pynchon's novel The Crying of Lot 49. In the novel, W.A.S.T.E. is (among other things) an underground postal service.

TorChat was a peer-to-peer anonymous instant messenger that used Tor onion services as its underlying network. It provided cryptographically secure text messaging and file transfers. The characteristics of Tor's onion services ensure that all traffic between the clients is encrypted and that it is very difficult to tell who is communicating with whom and where a given client is physically located.

Jimm is an alternative open-source instant messaging client for the ICQ network. It is written in Java ME and should work in most of mobile devices that follow MIDP specification.

Wengo was at the beginning of 2004 a subsidiary of French telecom service provider Neuf Cegetel. As of February 2012, Wengo employs 80 people in the Paris headquarters, and is a subsidiary of Vivendi. Wengo is now repositioned as an online personal and consulting services marketplace.

encrypted instant messenger app (IM)

Tkabber is a GPL instant messaging client for the XMPP protocol which uses the Tk toolkit for the GUI. It runs on anything to which Tcl/Tk is ported: almost any X-based system (namely, any Linux and *BSD, Solaris, etc.), Microsoft Windows, and Mac OS X.

computer network protocol

privacy preserving communication app

anonymized free instant messaging client

messaging and collaboration software by GNOME based on the Matrix protocol

__NOTOC__ climm (previously mICQ) is a free CLI-based instant messaging client that runs on a wide variety of platforms, including AmigaOS, BeOS, Windows (using either Cygwin or MinGW), OS X, NetBSD/OpenBSD/FreeBSD, Linux, Solaris, HP-UX, and AIX.