Rocket.Chat : Rocket.Chat is a Web Chat Server, developed in JavaScript, using the Meteor fullstack framework.
It is a great solution for communities and companies ...
Riot : Riot allows teams to communicate across a wide range of collaboration apps. If some team members use Riot while others use IRC, Slack or Gitter, Riot ...
extramuros : This is software for collaborative live coding. On one machine, you run an extramuros "server". Then, from as many machines as you like, you use a web...
Matrix : Matrix is an open standard for decentralised communication, providing simple HTTP APIs and open source reference implementations for securely distribu...
deepstream.io : A Scalable Server for Realtime Web Apps
Stores and syncs data in realtime
Built in node.js
Works for browsers, backend & mobile
Scales via clustering...
Zulip is a powerful, open source group chat application that combines the immediacy of real-time chat with the productivity benefits of threaded conversations.