Langfuse
Open-source platform for tracing, evaluations, and prompt management. Self-hostable alternative to LangSmith with clean UX.
Opik
Opik is an open-source LLM observability platform from Comet that provides detailed tracing, prompt tracking, and automated evaluation for AI applications. One-line integration captures every LLM call, cost, and output with built-in eval metrics including hallucination detection.