head to head · open source
Langfuse vs xerj
Langfuse has 36,898 GitHub stars, 4,146 forks, 926 open issues and last shipped yesterday. xerj has 18,817 stars, 1,435 forks, 16 open issues and last shipped yesterday. Langfuse leads on adoption by 96% (36,898 vs 18,817 stars). Langfuse is written in TypeScript under a custom or non-standard licence; xerj is written in Rust under Apache-2.0. Langfuse has attracted 11% as many forks as stars, xerj 8%. xerj was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | xerj | |
|---|---|---|
| GitHub stars | ★ 37K | ★ 19K |
| License | Custom / other | Apache-2.0 |
| Written in | TypeScript | Rust |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 4.1K | ⑂ 1.4K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Langfuse if
- You weight community size — 37K 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 xerj if
- You want the xerj feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and xerj fits your workflow better
About Langfuse
Langfuse Cloud · Self Host · Demo Docs · Report Bug · Feature Request · Changelog · Roadmap · Langfuse is an open source LLM engineering platform. It helps teams collaboratively develop, monitor, evaluate, and debug AI applications. Langfuse can be self hosted in minutes and is battle tested . Proudly made with ClickHouse open source database. 🧑💻 We're hiring Langfuse is growing fast (we doubled the team in the last 6 months) since January 2026 we're part of ClickHouse, we're hiring engineering hybrid across the EU. We hire engineers who love open source and great developer experiences. See open roles → ✨…
read the full Langfuse overview →
About xerj
XERJ XERJ is a community trusted local AI search that indexes any folder automatically, so your coding agent stops burning tokens reading files one by one and pulls the exact code it needs instead. Reference coding is its main use case and the clearest win: point an agent at a task and it downloads the open source repos closest to it, indexes them, and reuses how they solved the problem before writing its own code. In a controlled study that cut a coding agent's output tokens by 2.7x at the same 16/16 solve rate (case study), and people report roughly 5x in everyday work (field reports). It is enough for a…
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Frequently asked questions
Is Langfuse or xerj more popular?
Langfuse has 36,898 GitHub stars and xerj has 18,817. Langfuse has the larger community by that measure.
Are Langfuse and xerj free?
Both are open source. Langfuse has no licence declared in this registry, and xerj is licensed under Apache-2.0. Both are free to self-host.
What is the difference between Langfuse and xerj?
Langfuse is written in TypeScript and xerj in Rust. 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 xerj?
Choose Langfuse if you want the larger community (36,898 stars) or its Custom / other licence terms. Choose xerj if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.