Langfuse is an open-source platform for developing and monitoring applications built on language models and AI agents. It records detailed traces of model calls, tool use and retrieval steps, supports evaluation with LLM judges or human review, manages prompt versions and offers a playground, annotation workflows and dashboards for cost and latency. You can use Langfuse as a managed cloud service or host it yourself with Docker Compose, Kubernetes (Helm) or Terraform on AWS, GCP or Azure.
Langfuse was founded in Berlin. In January 2026 it was acquired by ClickHouse Inc., a company headquartered in the San Francisco Bay Area, so its ultimate parent is American. Langfuse is released under the MIT licence and, according to ClickHouse, remains open source, while Langfuse Cloud continues as a standalone service. The cloud offers regions in the EU (Ireland), the US and Japan, plus a separate HIPAA region. When self-hosting, all data stays in your own environment, which lets a European organisation limit exposure to the US jurisdiction of the parent company.