head to head · open source
Langfuse vs langchain4j
Langfuse has 34,729 GitHub stars, 3,785 forks, 926 open issues and last shipped yesterday. langchain4j has 13,116 stars, 2,555 forks, 878 open issues and last shipped 2 days ago. Langfuse leads on adoption by 165% (34,729 vs 13,116 stars). Langfuse is written in TypeScript under a custom or non-standard licence; langchain4j is written in Java under Apache-2.0. Langfuse has attracted 11% as many forks as stars, langchain4j 19%. Langfuse was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (langchain, llm), 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
| Langfuse | langchain4j | |
|---|---|---|
| GitHub stars | ★ 35K | ★ 13K |
| License | Custom / other | Apache-2.0 |
| Written in | TypeScript | Java |
| Last push | 2026-09-17 | 2026-09-16 |
| Forks | ⑂ 3.8K | ⑂ 2.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Langfuse if
- You weight community size — 35K stars and counting
- You want the Custom / other license terms
- Your stack matches TypeScript
- You value the larger contributor base for long-term maintenance
pick langchain4j if
- You want the langchain4j 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 langchain4j fits your workflow better
About Langfuse
Langfuse is an open source LLM engineering platform for building, monitoring, and improving AI powered applications. It lives in the LLMops ecosystem and provides tooling for the full development lifecycle—from prompt iteration and evaluation to observability and dataset management. Built with TypeScript and powered by ClickHouse, it enables teams to track LLM calls, user sessions, and internal logic like retrieval or agent actions in a unified interface.
read the full Langfuse overview →
About langchain4j
LangChain4j is an Apache 2.0, open source, idiomatic Java library for building LLM powered applications on the JVM, aimed at Java developers and enterprise teams who want one unified API over many LLM providers and embedding stores without leaving the Java ecosystem.
read the full langchain4j overview →
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Frequently asked questions
Is Langfuse or langchain4j more popular?
Langfuse has 34,729 GitHub stars and langchain4j has 13,116. Langfuse has the larger community by that measure.
Are Langfuse and langchain4j free?
Both are open source. Langfuse has no licence declared in this registry, and langchain4j is licensed under Apache-2.0. Both are free to self-host.
What is the difference between Langfuse and langchain4j?
Langfuse is written in TypeScript and langchain4j 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, Langfuse or langchain4j?
Choose Langfuse if you want the larger community (34,729 stars) or its Custom / other licence terms. Choose langchain4j if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.