Best LLM Observability Tools

Open-source LLM engineering platform that captures traces, runs evaluations, and helps teams analyze cost, latency, and quality across production AI apps.

Key Features:

• •Hierarchical Tracing & Agent Debugging
• •Production Prompt Management & Versioning
• •LLM-as-Judge Evaluation Framework

LangSmith helps developers trace, evaluate, test, and monitor applications built with language models and agent workflows.

Key Features:

• •Tracing for any LLM stack via Python/TypeScript SDKs or OpenTelemetry
• •LLM-as-judge, code-based and pairwise evaluations
• •Versioned prompts with production A/B traffic splits