The best Open Source alternatives to Slack in 2026
We compare 4 self-hostable tools you can deploy on your own server in minutes, with license, tech stack and a ready-to-copy docker-compose.
Rocket.Chat
Alternative to Slack
Self-hostable team chat, an alternative to Slack.
MIT 41k
Docker Ready1-Click DeployPermissive License
View profile and deployment guideMattermost
Alternative to Slack, Microsoft Teams
Security-focused team chat and collaboration, an alt. to Slack.
MIT 30k
Docker Ready1-Click DeployPermissive License
View profile and deployment guideHuly
Alternative to Linear, Notion, Slack
Projects + chat + docs in one, an alternative to Linear/Notion/Slack.
AGPL-3.0 11k
Docker Ready
View profile and deployment guideZulip
Alternative to Slack
Team chat organized by threads, an alternative to Slack.
Apache-2.0 21k
Docker ReadyPermissive License
View profile and deployment guide