Rocket.Chat is the leading free open source team chat Slack alternative, with 14.6k stars on GitHub and more than 600 contributors.
You can run Rocket.Chat on your infrastructure and be in complete control of your data and platform.
It features free audio and video conferencing, guest access, screen sharing, file sharing, LiveChat, LDAP Group Sync, two-factor authentication (2FA), E2E encryption, SSO, dozens of OAuth providers and unlimited: Users, Guests, Channels, Messages, Searches, Files.
With Rocket.Chat LiveChat you can add real-time chat widgets to any website or mobile app and get more value from your team chat, ditch other systems and use one communication platform to save time and money, and eventually create a user support helpdesk, answer customer queries and convert leads.
Rocket.Chat uses cutting edge machine learning for automatic real-time message translation between users.