head to head · open source
OpenObserve vs client_java
OpenObserve has 22,027 GitHub stars, 1,098 forks, 598 open issues and last shipped today. client_java has 2,289 stars, 833 forks, 23 open issues and last shipped today. OpenObserve leads on adoption by 862% (22,027 vs 2,289 stars). OpenObserve is written in TypeScript under AGPL-3.0; client_java is written in Java under Apache-2.0. OpenObserve has attracted 5% 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 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
| OpenObserve | client_java | |
|---|---|---|
| GitHub stars | ★ 22K | ★ 2.3K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | TypeScript | Java |
| Last push | 2026-09-20 | 2026-09-20 |
| Forks | ⑂ 1.1K | ⑂ 833 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenObserve if
- You weight community size — 22K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches TypeScript
- 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 OpenObserve
OpenObserve is an open source observability platform for logs, metrics, traces, analytics, Real User Monitoring, session replay, pipelines, SLO, and LLM observability. It lives in the cloud native infrastructure ecosystem and is described as an alternative to Datadog, Splunk, and Elasticsearch. The project is built in Rust, ships as a single binary, and uses Parquet columnar storage with an S3 native design.
read the full OpenObserve 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 →
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Frequently asked questions
Is OpenObserve or client_java more popular?
OpenObserve has 22,027 GitHub stars and client_java has 2,289. OpenObserve has the larger community by that measure.
Are OpenObserve and client_java free?
Both are open source. OpenObserve is licensed under AGPL-3.0 and client_java under Apache-2.0. Neither carries a licence fee.
What is the difference between OpenObserve and client_java?
OpenObserve is written in TypeScript 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, OpenObserve or client_java?
Choose OpenObserve if you want the larger community (22,027 stars) or its AGPL-3.0 licence terms. Choose client_java if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.