The Secure CommsOS™ for mission-critical operations
Rocket.Chat is an open-source, secure, fully customizable communications platform developed in TypeScript for organizations with high standards of data protection.
Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..
Jitsi Meet - Secure, Simple and Scalable Video Conferences that you use as a standalone app or embed in your web application.
Zulip server and web application. Open-source team chat that helps teams stay productive and focused.
A glossy Matrix collaboration client for the web.
Mumble is an open-source, low-latency, high quality voice chat software.
Synapse: Matrix homeserver written in Python/Twisted + Rust