head to head · open source
Mattermost vs certspotter
Mattermost has 39,101 GitHub stars, 9,006 forks, 1,012 open issues and last shipped today. certspotter has 1,175 stars, 104 forks, 18 open issues and last shipped 6 days ago. Mattermost leads on adoption by 3,228% (39,101 vs 1,175 stars). Mattermost is written in TypeScript under a custom or non-standard licence; certspotter is written in Go under MPL-2.0. Mattermost has attracted 23% as many forks as stars, certspotter 9%. 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 | certspotter | |
|---|---|---|
| GitHub stars | ★ 39K | ★ 1.2K |
| License | Custom / other | MPL-2.0 |
| Written in | TypeScript | Go |
| Last push | 2026-09-19 | 2026-09-13 |
| Forks | ⑂ 9.0K | ⑂ 104 |
| 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 certspotter if
- You want the certspotter feature set and don't need the biggest community
- You prefer the MPL-2.0 license terms
- Your stack matches Go
- You evaluated both and certspotter 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 certspotter
Cert Spotter is a lightweight, open source Certificate Transparency log monitor from SSLMate that watches Certificate Transparency logs and alerts you when an SSL/TLS certificate is issued for any domain on your watch list, aimed at site operators, security teams, and PKI administrators who need to catch unauthorized certificates without operating a database.
read the full certspotter overview →
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Frequently asked questions
Is Mattermost or certspotter more popular?
Mattermost has 39,101 GitHub stars and certspotter has 1,175. Mattermost has the larger community by that measure.
Are Mattermost and certspotter free?
Both are open source. Mattermost has no licence declared in this registry, and certspotter is licensed under MPL-2.0. Both are free to self-host.
What is the difference between Mattermost and certspotter?
Mattermost is written in TypeScript and certspotter in Go. 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 certspotter?
Choose Mattermost if you want the larger community (39,101 stars) or its Custom / other licence terms. Choose certspotter if its feature set, stack or MPL-2.0 licence fits better. Both are self-hostable.