head to head · open source
Mattermost vs Fluxer
Mattermost has 39,093 GitHub stars, 9,000 forks, 1,012 open issues and last shipped yesterday. Fluxer has 10,299 stars, 758 forks, 111 open issues and last shipped yesterday. Mattermost leads on adoption by 280% (39,093 vs 10,299 stars). Mattermost is written in TypeScript under a custom or non-standard licence; Fluxer is written in TypeScript under AGPL-3.0. Mattermost has attracted 23% as many forks as stars, Fluxer 7%. 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 | Fluxer | |
|---|---|---|
| GitHub stars | ★ 39K | ★ 10K |
| License | Custom / other | AGPL-3.0 |
| Written in | TypeScript | TypeScript |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 9.0K | ⑂ 758 |
| 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 Fluxer if
- You want the Fluxer feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches TypeScript
- You evaluated both and Fluxer 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 Fluxer
Fluxer is a free and open source instant messaging and VoIP chat application built for friends, groups, and communities. The project's tagline describes it as messaging with privacy and community focus, and the GitHub description repeats the same core purpose. The repository is written in TypeScript and is distributed under the AGPL 3.0 license.
read the full Fluxer overview →
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Frequently asked questions
Is Mattermost or Fluxer more popular?
Mattermost has 39,093 GitHub stars and Fluxer has 10,299. Mattermost has the larger community by that measure.
Are Mattermost and Fluxer free?
Both are open source. Mattermost has no licence declared in this registry, and Fluxer is licensed under AGPL-3.0. Both are free to self-host.
What is the difference between Mattermost and Fluxer?
Mattermost is written in TypeScript and Fluxer 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 Fluxer?
Choose Mattermost if you want the larger community (39,093 stars) or its Custom / other licence terms. Choose Fluxer if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.