Langfuse (YC W23) — Open source LLM engineering platform
Traces, evals, prompt management and metrics to debug and improve your LLM application. Onboard via https://langfuse.com Langfuse helps you build and improve LLM applications across the entire lifecycle: - Develop: Observability, Langfuse UI & Prompt Management - Monitor: Traces, Analytics, Metrics & Evaluations - Test: Experiments, Releases & Datasets We are hiring: https://langfuse.com/careers Langfuse was acquired by Clickhouse in January of 2026.
Langfuse is a Y Combinator company in the Winter 2023 batch. Its directory entry describes it as: Open source LLM engineering platform. The founders listed are Marc Klingen (Founder/CEO), Maximilian Deichmann (Founder), Clemens Rawert (Founder) (Y Combinator directory entry, January 16, 2023).
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Example from a real report (our sample on Target): “The Q2 2026 earnings report, published August 19, 2026, showed adjusted EPS of $2.46 against an expected $2.33” Source: CNBC
Traces, evals, prompt management and metrics to debug and improve your LLM application.
Onboard via https://langfuse.com
Langfuse helps you build and improve LLM applications across the entire lifecycle:
- Develop: Observability, Langfuse UI & Prompt Management
- Monitor: Traces, Analytics, Metrics & Evaluations
- Test: Experiments, Releases & Datasets
We are hiring: https://langfuse.com/careers
Langfuse was acquired by Clickhouse in January of 2026.
Marc Klingen
Founder/CEO
Maximilian Deichmann
Founder
Clemens Rawert
Founder
Founders, titles and bios as the company published them. Photographs are our own copies of the ones on that record, so they do not break when the original link expires.
One of 641 companies held here in B2B › Engineering, Product and Design.
No investor is drawn from a Form D — the form states how many invested and never who. The one investor on this graph is named because a batch has exactly one.
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Example from a real report (our sample on Target): “The Q2 2026 earnings report, published August 19, 2026, showed adjusted EPS of $2.46 against an expected $2.33” Source: CNBC
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