Langfuse

Langfuse is an open-source platform that helps teams build and improve applications based on large language models. It records hierarchical traces of model calls, tool use and retrieval steps, then lets teams evaluate outputs with model-based judges, custom checks or human review. A prompt management layer separates prompts from code with versioning and a playground, and datasets and experiments let teams compare changes before release. Cost and latency dashboards track usage. Langfuse can be self-hosted under an MIT license or used as a managed cloud service, and joined ClickHouse in 2026.