Pidgin

Open Source

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

Viber

Freemium

Viber Free Messenger and Phone Calls.

Jitsi

Open Source

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

Wire

Free

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…

ICQ

Free

ICQ is an open source instant messaging software.

Off-the-Record Messaging

Open Source

Off-the-Record Messaging (OTR) is a cryptographic protocol that provides encryption for instant messaging conversations.

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…

Rambox

Open Source

Rambox is a free and Open Source messaging and emailing app that combines common web applications into one.

Zulip

Open Source

Zulip is a chat and collaborative software.

Tox

Open Source

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

Signal

Open Source

Signal is the most scalable encryption tool.

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.

Gajim

Open Source

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

Instantbird

Open Source

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

Torchat

Open Source

TorChat is a decentralized anonymous instant messenger that uses Tor hidden services as its underlying network. It provides cryptographically secure text mess…