Langfuse

Langfuse is an open-source LLM engineering platform that provides observability, analytics, and evaluation tools for AI applications. Langfuse enables developers to trace LLM calls, monitor agent execution, track costs, evaluate output quality, and manage prompts across their AI systems.

As an open-source alternative to proprietary observability platforms, Langfuse has gained strong adoption among developers who want full control over their observability data. The platform integrates with all major agent frameworks (LangChain, LlamaIndex, OpenAI SDK) and supports self-hosting for organizations with data privacy requirements.

Langfuse addresses the growing need for production observability in the agentic economy — as AI agents handle more critical workflows, teams need detailed visibility into what agents are doing, how much it costs, and whether outputs meet quality standards.