6 self-hosted options
Open-source alternatives to Slack
The best open-source alternatives to Slack are Mattermost, Rocket.Chat and Zulip.
About Slack: A team messaging platform with channels, threads and integrations.
Every option below is free to self-host and ranked by GitHub stars, so you can move off Slack without giving up the features you rely on.
Top picks
- Rank 1:
Mattermost
mattermost/mattermost
Platform for secure collaboration across the entire software development lifecycle, can be integrated with Gitlab (alternative to Slack).
Team ChatTypeScriptDocker - Rank 2:
Rocket.Chat
RocketChat/Rocket.Chat
Communications platform that puts data protection first (alternative to Gitter.im and Slack).
Team ChatTypeScriptDocker - Rank 3:
Zulip
zulip/zulip
Zulip is a powerful, open source group chat application.
Team ChatPython
Why switch
Why teams move off Slack
Self-hosting is not only about saving money. These are the reasons people make the switch.
Own your data
Your data lives on a server you control, not on Slack's infrastructure. No surprise policy changes and no lock-in.
No per-seat pricing
Open-source alternatives to Slack are free to run for as many users as your server can handle. A small VPS often costs less than a single subscription.
Customize and extend
Read the code, add plugins, connect it to your own tools and automate it through open APIs. When you need a feature, you can build it or fund it.
Full ranking
All 6 Slack alternatives
Ranked by GitHub stars. Open any app for live stats, license details and a deploy option.
- 1
Mattermost
Platform for secure collaboration across the entire software development lifecycle, can be integrated with Gitlab (alternative to Slack).
Team ChatDocker - 2
Rocket.Chat
Communications platform that puts data protection first (alternative to Gitter.im and Slack).
Team ChatDocker - 3
Zulip
Zulip is a powerful, open source group chat application.
Team Chat - 4
Element
Fully-featured Matrix client for Web, iOS & Android.
Team Chat - 5
Synapse
Server for Matrix, an open standard for decentralized persistent communication.
Team Chat - 6
Stoat
Stoat is a user-first chat platform built with modern web technologies.
Team ChatDocker
What is the best open-source alternative to Slack?
Mattermost is the most popular open-source alternative to Slack, with 39,271 GitHub stars. Rocket.Chat and Zulip are also strong choices. Compare features, license and recent activity to find the best fit for your team.
Is there a free alternative to Slack?
Yes. All 6 apps on this page are open source and free to self-host, so you can run a Slack replacement without per-user fees. You only pay for the server, and a small VPS is usually enough for personal use or a small team.
Can I self-host an alternative to Slack?
Yes. Mattermost, Rocket.Chat and Stoat ship a Docker image, so you can run them on a home server or VPS with Docker Compose in a few minutes. Your data then stays on hardware you control.
How do I migrate from Slack?
Start by exporting your data from Slack, then check the import options of the app you pick, since many projects ship importers for popular formats. Run both side by side for a week before you switch so nothing is lost.