Langfuse Freemium

Langfuse is an open-source LLM engineering platform that gives teams full observability into their AI applications. It provides tracing, metrics, and evaluation tools so developers can debug prompts, monitor cost and latency, and continuously improve model quality.

With Langfuse, you can log every request, compare prompt versions, and run evals to catch regressions before users do. It is the tool of choice for ML engineers who need production-grade visibility into how their LLM products actually behave.