Langfuse
Open source tracing and analytics for LLM applications
Langfuse launched on August 20, 2023 with 771 votes, #11 of 4,347 launches that month and more than 99% of that year's launches. The site was still online in September 2026, 3 years on.
In plain words
Langfuse is an open-source observability platform for developers building LLM applications. It provides visual tracing and logging tools to explore and debug complex application behavior, along with analytics dashboards that track costs, latency, and response quality. The platform helps teams monitor and optimize their language model applications through intuitive interfaces and detailed performance metrics.
written from the facts on this page · September 2026
From the sources
Langfuse provides open-source observability and analytics for LLM apps. Observability: Explore and debug complex logs & traces in a visual UI. Analytics: Improve costs, latency and response quality using intuitive dashboards.
Trace, evaluate, and improve AI agents with one open platform. Use production data to understand behavior, collaborate on fixes, and ship better quality at lower cost and latency.
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Langfuse – Open-source observability and analytics for LLM apps2023 · github.com · ▲143Hi HN! Langfuse is OSS observability and analytics for LLM applications (repo: https://github.com/langfuse/langfuse, 2 min demo: https://langfuse.com/video, try it yourself: https://langfuse.com/demo) Langfuse makes capturing and viewing LLM calls (execution traces) a breeze. On top of this data, you can analyze the quality, cost and latency of LLM apps. When GPT-4 dropped, we started building LLM apps – a lot of them! [1, 2] But they all suffered from the same issue: it’s hard to assure quality in 100% of cases and even to have a clear view…
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