Open-source Slack alternatives
5 self-hostable options to consider
Replace Slack with an open-source tool you can host and control. Compare features, licenses, and community activity below.
Quick answer
The best open-source Slack alternatives are Rocket.Chat, Mattermost, Zulip, Element, and Chatto. All 5 are free, open source, and self-hostable — compare their features, licenses, and GitHub activity below.
5 tools
Rocket.Chat
Alternative to Slack, Microsoft Teams
A customizable communications platform.
Open SourceMIT42K
Mattermost
Alternative to Slack, Microsoft Teams
Secure team messaging for technical teams.
Open SourceSource Available33K
Zulip
Alternative to Slack, Discord
Threaded team chat that scales with focus.
Open SourceApache 2.022K
