head to head · open source
Apache SkyWalking vs mulog
Apache SkyWalking has 24,958 GitHub stars, 6,633 forks, 41 open issues and last shipped 3 days ago. mulog has 540 stars, 49 forks, 12 open issues and last shipped 3 months ago. Apache SkyWalking leads on adoption by 4,522% (24,958 vs 540 stars). Apache SkyWalking is written in Java under Apache-2.0; mulog is written in Clojure under Apache-2.0. Apache SkyWalking has attracted 27% as many forks as stars, mulog 9%. Apache SkyWalking was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (logging, observability), so they are genuine substitutes rather than adjacent tools.
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
| Apache SkyWalking | mulog | |
|---|---|---|
| GitHub stars | ★ 25K | ★ 540 |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Java | Clojure |
| Last push | 2026-09-17 | 2026-06-27 |
| Forks | ⑂ 6.6K | ⑂ 49 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Apache SkyWalking if
- You weight community size — 25K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Java
- You value the larger contributor base for long-term maintenance
pick mulog if
- You want the mulog feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Clojure
- You evaluated both and mulog fits your workflow better
About Apache SkyWalking
Apache SkyWalking is an open source application performance monitoring (APM) system for distributed systems in cloud native architectures, built for teams that run microservices across Kubernetes and container based environments.
read the full Apache SkyWalking overview →
About mulog
μ/log is an Apache 2.0 Clojure micro logging library that logs events and data points rather than formatted words, aimed at Clojure developers building distributed systems who want logs, metrics and traces to come out of one event stream.
read the full mulog overview →
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Frequently asked questions
Is Apache SkyWalking or mulog more popular?
Apache SkyWalking has 24,958 GitHub stars and mulog has 540. Apache SkyWalking has the larger community by that measure.
Are Apache SkyWalking and mulog free?
Both are open source. Apache SkyWalking is licensed under Apache-2.0 and mulog under Apache-2.0. Neither carries a licence fee.
What is the difference between Apache SkyWalking and mulog?
Apache SkyWalking is written in Java and mulog in Clojure. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Apache SkyWalking or mulog?
Choose Apache SkyWalking if you want the larger community (24,958 stars) or its Apache-2.0 licence terms. Choose mulog if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.