Langfuse
Open-source LLM engineering platform
Langfuse provides LLM observability, prompt management, evaluations, and datasets. Open source with a managed cloud option. The leading open alternative to LangSmith.
Panel Reviews
The Builder
Developer Perspective
“Best open-source LLM observability. Traces, prompt versioning, and evals in one tool. Self-hosting option is a must.”
The Skeptic
Reality Check
“Open source means no vendor lock-in. The tracing UI is clean and the integration with LangChain and Vercel AI SDK is seamless.”
The Futurist
Big Picture
“LLM observability is becoming as essential as APM. Langfuse is the Grafana of AI — open source and community-driven.”
Community Sentiment
“Open source alternative to LangSmith that doesn't lock you into their pricing”
“Prompt management + traces in one tool saved us from the LangSmith bill”
“Langfuse evals caught a prompt regression before it hit production — worth every penny”
“The dataset management for evals is exactly what was missing from the OSS ecosystem”