head to head · open source
Mattermost vs Zulip
Mattermost has 39,096 GitHub stars, 9,005 forks, 1,012 open issues and last shipped today. Zulip has 25,922 stars, 10,250 forks, 2,008 open issues and last shipped yesterday. Mattermost leads on adoption by 51% (39,096 vs 25,922 stars). Mattermost is written in TypeScript under a custom or non-standard licence; Zulip is written in Python under Apache-2.0. Mattermost has attracted 23% as many forks as stars, Zulip 40%. Mattermost was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (collaboration, react-native), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Mattermost | Zulip | |
|---|---|---|
| GitHub stars | ★ 39K | ★ 26K |
| License | Custom / other | Apache-2.0 |
| Written in | TypeScript | Python |
| Last push | 2026-09-18 | 2026-09-17 |
| Forks | ⑂ 9.0K | ⑂ 10K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Mattermost if
- You weight community size — 39K stars and counting
- You want the Custom / other license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick Zulip if
- You want the Zulip feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and Zulip fits your workflow better
About Mattermost
Mattermost is an open core, self hosted collaboration platform for teams that need secure chat, workflow automation, voice calling, screen sharing, and AI integration while keeping the deployment under their own control.
read the full Mattermost overview →
About Zulip
Zulip is an open source organized team chat application built on topic based threading, aimed at distributed teams that need live and asynchronous conversation in one place, and it is positioned as an open alternative to Slack.
read the full Zulip overview →
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Frequently asked questions
Is Mattermost or Zulip more popular?
Mattermost has 39,096 GitHub stars and Zulip has 25,922. Mattermost has the larger community by that measure.
Are Mattermost and Zulip free?
Both are open source. Mattermost has no licence declared in this registry, and Zulip is licensed under Apache-2.0. Both are free to self-host.
What is the difference between Mattermost and Zulip?
Mattermost is written in TypeScript and Zulip in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Mattermost or Zulip?
Choose Mattermost if you want the larger community (39,096 stars) or its Custom / other licence terms. Choose Zulip if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.