Langfuse

Langfuse is an open-source AI engineering platform for developing, monitoring, evaluating, and debugging production LLM applications and AI agents. Its products include LLM observability and tracing, prompt management, evaluations, datasets, testing workflows, and collaboration tools, available through cloud and self-hosted deployments.

Founded by Marc Klingen, Max Deichmann, and Clemens Rawert, the company participated in Y Combinator’s Winter 2023 batch and was acquired by ClickHouse in January 2026. Langfuse operates primarily from Berlin for product and engineering, with a San Francisco office focused on go-to-market activities.