What Langfuse does
Langfuse is an open-source platform for building, monitoring, and improving LLM applications and agents. It records LLM calls, tool invocations, and retrieval steps as traces, with filters for user, session, cost, latency, and custom metadata. Teams use it to run evaluations with LLM-as-a-judge, heuristic functions, or human review, and to manage prompts separately from code with deployments and rollbacks. Other features include experiments, datasets, a playground, and OpenTelemetry integrations. The site states that all product features are MIT licensed, and it offers a free cloud tier with 50k observations per month along with self-hosting options.
How Langfuse compares with its closest alternatives
4 of the 5 closest alternatives have a free plan, as Langfuse does. All 5 offer an API, as Langfuse does. Langfuse offers a web app and a desktop app. Of the alternatives, all 5 offer a web app and none offers a desktop app. Langfuse was founded in 2023; the alternatives were founded between 2016 and 2023, 1 of them earlier. Langfuse is based in San Francisco, United States; 4 of its 5 alternatives are in the United States too, and the others in Israel.