head to head · open source
Mattermost vs Phase
Mattermost has 39,093 GitHub stars, 9,000 forks, 1,012 open issues and last shipped yesterday. Phase has 923 stars, 70 forks, 78 open issues and last shipped 2 days ago. Mattermost leads on adoption by 4,135% (39,093 vs 923 stars). Mattermost is written in TypeScript under a custom or non-standard licence; Phase is written in TypeScript under a custom or non-standard licence. Mattermost has attracted 23% as many forks as stars, Phase 8%. Mattermost was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | Phase | |
|---|---|---|
| GitHub stars | ★ 39K | ★ 923 |
| License | Custom / other | Custom / other |
| Written in | TypeScript | TypeScript |
| Last push | 2026-09-17 | 2026-09-16 |
| Forks | ⑂ 9.0K | ⑂ 70 |
| 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 Phase if
- You want the Phase feature set and don't need the biggest community
- You prefer the Custom / other license terms
- Your stack matches TypeScript
- You evaluated both and Phase 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 Phase
Phase is an open source secrets management platform, written in TypeScript, that lets fast moving engineering teams secure, deploy, and manage application secrets and environment variables from development through to production.
read the full Phase overview →
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Frequently asked questions
Is Mattermost or Phase more popular?
Mattermost has 39,093 GitHub stars and Phase has 923. Mattermost has the larger community by that measure.
Are Mattermost and Phase free?
Neither Mattermost nor Phase declares a licence in this registry, so check each project's own repository before relying on either for a commercial use. Both are free to self-host.
What is the difference between Mattermost and Phase?
Mattermost is written in TypeScript and Phase in TypeScript. 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 Phase?
Choose Mattermost if you want the larger community (39,093 stars) or its Custom / other licence terms. Choose Phase if its feature set, stack or Custom / other licence fits better. Both are self-hostable.