Open Source Alternatives to Slack
2 community-validated alternatives found. All tools verified and tagged by real users.
Why switch from Slack?
Many users switch from Slack to open source alternatives for reasons including: data ownership and privacy, avoiding vendor lock-in, cost savings, and the ability to self-host on your own infrastructure. The tools listed here are community-validated alternatives that have been reviewed by real users.
Own Your Data
Self-host on your own servers. No vendor can access or delete your data.
No Surprise Pricing
Open source tools don't have surprise price hikes or feature gating.
Community Driven
Features are driven by the community, not by investor pressure.
Frequently Asked Questions
What is the best free alternative to Slack?
The top community-voted free alternatives to Slack are Mattermost and Rocket.Chat. All are open source and can be self-hosted on your own infrastructure.
Can I self-host an alternative to Slack?
Yes. Mattermost and Rocket.Chat are fully self-hostable — you can run them on your own server or VPS using Docker or native installs, with no recurring subscription fees.
What is the open source version of Slack?
Mattermost is the most popular open source alternative to Slack, with 28,000 GitHub stars and an active community. Self-hosted Slack alternative for teams.
Is there a free version of Slack?
Instead of a free tier of Slack, consider fully free and open source alternatives like Mattermost and Rocket.Chat. These tools are free forever, community-governed, and you own your data completely.