head to head · open source
Mattermost vs Fluxer
Mattermost has 39,510 GitHub stars, 9,087 forks, 1,012 open issues and last shipped yesterday. Fluxer has 10,750 stars, 844 forks, 111 open issues and last shipped yesterday. Mattermost leads on adoption by 268% (39,510 vs 10,750 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 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 | Fluxer | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 11K |
| License | Custom / other | AGPL-3.0 |
| Written in | TypeScript | TypeScript |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 9.1K | ⑂ 844 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Mattermost if
- You weight community size — 40K 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 that offers chat, workflow automation, voice calling, screen sharing, and AI integration. This repo is the primary source for core development on the Mattermost platform; it's written in Go and React, runs as a single Linux binary, and relies on PostgreSQL. A new compiled version is released under an MIT license every month on the 16th. Deploy Mattermost on premises, or try it for free in the cloud. Learn more about the following use cases with Mattermost: DevSecOps Incident Resolution IT Service Desk Other useful resources: Download and Install…
read the full Mattermost overview →
About Fluxer
Fluxer Fluxer is a free and open source instant messaging and VoIP chat app built for friends, groups, and communities.
read the full Fluxer overview →
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Frequently asked questions
Is Mattermost or Fluxer more popular?
Mattermost has 39,510 GitHub stars and Fluxer has 10,750. 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 (39,510 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.