Open Source Team Chat & Messaging Tools Projects

Open source AI-powered omnichannel customer service platform that combines live chat, ticketing, and team collaboration as an alternative to Slack, Zendesk, Intercom, and HubSpot.

A self-hosted chat application for teams and communities with video calls, voice calls, and screen sharing.

Open source, local-first Slack and Notion alternative that puts you in control of your data with offline support and end-to-end encryption.

Decentralized private messenger using email infrastructure for secure, end-to-end encrypted communication.

Open source community forum platform combining long-form discussion, real-time chat, and strong moderation. Self-host it or use managed hosting.

Open-source Matrix client for secure, decentralized messaging, voice, and video — runs on your own server.

A free and open source instant messaging and VoIP chat app for friends, groups, and communities.

All-in-one open source platform that combines project management, CRM, chat, HR, and wiki as an alternative to Linear, Jira, Slack, and Notion.

Lightweight, Google-searchable open source Slack and Discord alternative designed for online communities.

Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..

Low-latency, open-source voice chat built for gaming — self-host your own server with no subscription required.

Private, peer-to-peer Slack and Discord alternative built on Tor and IPFS that needs no servers and no accounts.

Simple, open source team messaging platform

Self-hosted team chat with channels, threads, voice and video calls, federation, plus desktop and mobile apps.

Self-hosted chat server with voice, video, text, and screen sharing — Discord-like features on your own infrastructure.

Instant messaging platform with self-hosted backend in Go and clients for iOS, Android, web, and command line.

Open-source team chat with a unique topic-based threading model that makes it easy to follow multiple conversations.