Secure, self-hosted team messaging platform as an alternative to Slack
36k
Stars
8.5k
Forks
850
Contributors
N/A
Last Commit
Mattermost can be used as an alternative to these commercial products.
Similar projects you might find useful.
Open source team communication platform — Slack alternative with channels, DMs, video calls, and federation
Decentralized messaging app built on Matrix — encrypted team chat, video calls, and bridges to other platforms
Open source video conferencing solution that is secure and easy to deploy
Open source web conferencing system for online learning — Zoom alternative with whiteboard and breakout rooms
Mattermost is the best open source alternative to Slack in 2026. Self-hosted team chat, MIT license, no per-seat fees — replaces Slack Pro at $8.75/user/month.
Self-host Mattermost vs Slack in 2026: cost per seat, admin features, and migration steps compared. Mattermost saves $12/user/month for 20+ person teams.
Self-host Mattermost as a Slack alternative for teams in 2026. MIT license, ~30K stars — channels, threads, integrations, bots, slash commands for 2026.
SaaS to self-hosted, step-by-step — one PDF.
Join 300+ self-hosters. No spam.