Langfuse

Langfuse is an engineering platform for observability, testing and monitoring large language model (LLM) applications. Its SDKs support Python, JavaScript and TypeScript, OpenAI, LangChain and LiteLLM among other languages and frameworks. You can self-host the open-source version or use it as a paid cloud service. Our teams have had a positive experience, particularly in debugging complex LLM chains, analyzing completions and monitoring key metrics such as cost and latency across users, sessions, geographies, features and model versions. If you’re looking to build data-driven LLM applications, Langfuse is a good option to consider.