Langfuse

Langfuse is an open-source LLM engineering platform designed to help developers debug, evaluate, and continuously improve their large language model applications. Acquired by ClickHouse, Langfuse provides robust observability features by capturing complete traces of LLM applications and agents natively through OpenTelemetry. With dedicated SDKs for Python and JS/TS, as well as a flexible public API, developers can effortlessly integrate Langfuse into their workflows—often using just a drop-in wrapper or the @observe decorator for popular integrations like OpenAI. Core capabilities include advanced trace capture, evaluation dataset building, centralized prompt management, and high-level metric tracking. By enabling teams to closely inspect execution failures, annotate outputs, and iterate safely in a built-in playground, Langfuse drastically reduces the time needed to optimize complex agentic behaviors. Because of its open-source nature, teams can choose to utilize the managed cloud platform or self-host the infrastructure entirely, ensuring strict data compliance and security for enterprise workloads.