Open Source Instant Messengers

An encrypted messaging app focused on privacy, supporting texts, calls, photos, videos, files, and group chats, with no ads or trackers.

A secure collaboration app with end-to-end encryption and interoperability across web, desktop, and mobile. Includes chat, voice, and video calls.

Matrix defines a set of open APIs for decentralised communication, suitable for securely publishing, persisting and subscribing to data over a global open federation of servers with no single point of control.

Pidgin is a chat program which lets you log into accounts on multiple chat networks simultaneously. This means that you can be chatting with friends on XMPP and sitting in an IRC channel at the same time.

With the rise of widespread government monitoring programs, Tox is an easy to use application that allows you to connect with friends and loved ones without anyone else listening in.

SimpleX - the most private and secure chat and applications platform - now with double ratchet E2E encryption! Built on Haskell with Love and Coffee.

Jami (formerly GNU Ring, SFLphone) positions itself as a potential free Skype replacement

Stoat (previously Revolt) is a chat platform that puts users first. With text & voice channels, video calling, screen sharing, permissions, mod tools, bots & more. Join any community or build one just the way you like it. It also respects your privacy.

Wire is the most secure collaboration platform featuring messenger, voice, video, conference calls, file-sharing, and external collaboration –all protected by the most secure end-to-end-encryption.

Threema is a new mobile messaging app that puts security first. With true end-to-end encryption, you can rest assured that only you and the intended recipient can read your messages.

An open-source decentralized and encrypted messaging app even without internet connection via Wi-Fi and Bluetooth. Messages are stored securely on your device, not in the cloud. Connect directly with nearby contacts - no Internet access is required.

Jitsi Desktop (previously SIP Communicator) is a legacy audio/video and chat communicator with full encryption, precedessor of Jitsi Meet .

Fossify Messenger is your trusted messaging companion, designed to enhance your messaging experience in various ways.

Station is the first open-source smart browser for busy people. A single place for all of your web applications.

Mattermost is a secure, open source platform for communication, collaboration, and workflow orchestration across tools and teams.

All your services in one place, built by the community.

RetroShare is a open source cross-platform, private and secure decentralized communication system. It lets you to securely chat, share photos, videos, and more, using OpenPGP to authenticate peers and .

Molly is an independent Signal fork for Android.

It is the brand new, and fastest ever, Matrix client. It is for personal and community use, and will support enterprise functionality later this year.

Uses email as a decentralized chat platform with modern interface, open source code, no central servers, strong privacy controls, and no account signup.

Rocket.Chat is a Web Chat Server, developed in JavaScript, using the Meteor fullstack framework.

QUIK is an open source replacement to the stock messaging app on Android. It is a continuation of QKSMS.

Linphone is one of the most famous open source softphones in the world. It is fully SIP-based, for all calling, presence and IM features.

FluffyChat is an open, nonprofit and cute matrix messenger app for Ubuntu Touch, Android and iOS.

Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG].