head to head · open source
Uptime Kuma vs defmt
Uptime Kuma has 91,498 GitHub stars, 8,431 forks, 805 open issues and last shipped yesterday. defmt has 1,228 stars, 132 forks, 117 open issues and last shipped 11 days ago. Uptime Kuma leads on adoption by 7,351% (91,498 vs 1,228 stars). Uptime Kuma is written in JavaScript under MIT; defmt is written in Rust under Apache-2.0. Uptime Kuma has attracted 9% as many forks as stars, defmt 11%. Uptime Kuma 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
| Uptime Kuma | defmt | |
|---|---|---|
| GitHub stars | ★ 91K | ★ 1.2K |
| License | MIT | Apache-2.0 |
| Written in | JavaScript | Rust |
| Last push | 2026-09-18 | 2026-09-08 |
| Forks | ⑂ 8.4K | ⑂ 132 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Uptime Kuma if
- You weight community size — 91K stars and counting
- You want the MIT license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick defmt if
- You want the defmt feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and defmt fits your workflow better
About Uptime Kuma
Uptime Kuma is a free, MIT licensed, self hosted monitoring tool with a reactive web dashboard, built for operators and teams that want to watch their own HTTP, TCP, and DNS endpoints and keep the resulting data on their own infrastructure.
read the full Uptime Kuma overview →
About defmt
defmt is an efficient, deferred formatting logging framework for embedded systems written in Rust, aimed at firmware developers building for resource constrained devices such as microcontrollers.
read the full defmt overview →
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Frequently asked questions
Is Uptime Kuma or defmt more popular?
Uptime Kuma has 91,498 GitHub stars and defmt has 1,228. Uptime Kuma has the larger community by that measure.
Are Uptime Kuma and defmt free?
Both are open source. Uptime Kuma is licensed under MIT and defmt under Apache-2.0. Neither carries a licence fee.
What is the difference between Uptime Kuma and defmt?
Uptime Kuma is written in JavaScript and defmt in Rust. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Uptime Kuma or defmt?
Choose Uptime Kuma if you want the larger community (91,498 stars) or its MIT licence terms. Choose defmt if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.