head to head · open source
Apache SkyWalking vs client_java
Apache SkyWalking has 24,958 GitHub stars, 6,633 forks, 41 open issues and last shipped 3 days ago. client_java has 2,289 stars, 833 forks, 23 open issues and last shipped today. Apache SkyWalking leads on adoption by 990% (24,958 vs 2,289 stars). Apache SkyWalking is written in Java under Apache-2.0; client_java is written in Java under Apache-2.0. Apache SkyWalking has attracted 27% as many forks as stars, client_java 36%. client_java was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (metrics, prometheus), 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.
← all 20902 open source comparisons
Side by side
| Apache SkyWalking | client_java | |
|---|---|---|
| GitHub stars | ★ 25K | ★ 2.3K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Java | Java |
| Last push | 2026-09-17 | 2026-09-20 |
| Forks | ⑂ 6.6K | ⑂ 833 |
| 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 client_java if
- You want the client_java feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and client_java 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 client_java
Prometheus instrumentation library for JVM applications — it lets Java services expose metrics that Prometheus scrapes, and it is aimed at Java and JVM developers and the platform, SRE, and observability teams that run Prometheus alongside them.
read the full client_java overview →
More in Infrastructure & Operations
Related comparisons
More Monitoring & Observability projects
Compare either of these against the rest of the Monitoring & Observability field.
Frequently asked questions
Is Apache SkyWalking or client_java more popular?
Apache SkyWalking has 24,958 GitHub stars and client_java has 2,289. Apache SkyWalking has the larger community by that measure.
Are Apache SkyWalking and client_java free?
Both are open source. Apache SkyWalking is licensed under Apache-2.0 and client_java under Apache-2.0. Neither carries a licence fee.
What is the difference between Apache SkyWalking and client_java?
Apache SkyWalking is written in Java and client_java in Java. 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 client_java?
Choose Apache SkyWalking if you want the larger community (24,958 stars) or its Apache-2.0 licence terms. Choose client_java if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.