Langfuse

Helicone is an open-source proxy and observability platform for LLM applications, offering request tracing, caching, and cost analytics.

Phoenix is an open-source observability and evaluation tool for LLM and agent applications, supporting online tracing and offline diagnosis.

TruLens is an open-source tool for evaluating and tracking LLM apps. It provides specialized evaluation for RAG applications including context relevance, groundedness, and answer relevance.

AgentOps is an observability platform for AI agents, providing monitoring, debugging, and evaluation to help developers optimize agent performance.