head to head · open source
Apache SkyWalking vs resilience4j
Apache SkyWalking has 24,958 GitHub stars, 6,633 forks, 41 open issues and last shipped 3 days ago. resilience4j has 10,765 stars, 1,502 forks, 306 open issues and last shipped 20 days ago. Apache SkyWalking leads on adoption by 132% (24,958 vs 10,765 stars). Apache SkyWalking is written in Java under Apache-2.0; resilience4j is written in Java under Apache-2.0. Apache SkyWalking has attracted 27% as many forks as stars, resilience4j 14%. Apache SkyWalking was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (metrics), 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 | resilience4j | |
|---|---|---|
| GitHub stars | ★ 25K | ★ 11K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Java | Java |
| Last push | 2026-09-17 | 2026-08-31 |
| Forks | ⑂ 6.6K | ⑂ 1.5K |
| 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 resilience4j if
- You want the resilience4j 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 resilience4j 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 resilience4j
Resilience4j is a lightweight fault tolerance library for Java, designed around functional programming. It lives in the Java ecosystem and is distributed under the Apache 2.0 license. The library provides higher order functions, called decorators, that enhance any functional interface, lambda expression or method reference with a Circuit Breaker, Rate Limiter, Retry or Bulkhead. Version 3 of the library requires Java 21, while the project originated as a library for Java 8. The repository has been active for roughly eleven years and carries 10,760 stars, 1,499 forks and 306 open issues.
read the full resilience4j overview →
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Frequently asked questions
Is Apache SkyWalking or resilience4j more popular?
Apache SkyWalking has 24,958 GitHub stars and resilience4j has 10,765. Apache SkyWalking has the larger community by that measure.
Are Apache SkyWalking and resilience4j free?
Both are open source. Apache SkyWalking is licensed under Apache-2.0 and resilience4j under Apache-2.0. Neither carries a licence fee.
What is the difference between Apache SkyWalking and resilience4j?
Apache SkyWalking is written in Java and resilience4j 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 resilience4j?
Choose Apache SkyWalking if you want the larger community (24,958 stars) or its Apache-2.0 licence terms. Choose resilience4j if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.