Langfuse
Open source LLM engineering platform for tracing, evaluating, monitoring, and managing prompts as an alternative to LangSmith and Helicone.
Langfuse is an open source LLM engineering platform that helps teams debug, evaluate, monitor, and manage prompts for production AI applications. It is a popular self-hostable alternative to LangSmith and Helicone for teams that want full control of their LLM telemetry.
Langfuse provides detailed tracing of LLM calls, OpenTelemetry-native instrumentation, automatic prompt versioning, evaluation datasets, and a managed playground for prompt engineering. It integrates with LangChain, OpenAI, LiteLLM, Anthropic, and the broader OpenTelemetry ecosystem.
Released under an MIT-style license and built with TypeScript and Python, Langfuse is widely used by startups and enterprises that need an open, vendor-neutral observability stack for LLM-powered products.