Best LLM Observability Tools 2026 — Community Ranked

LangChain's official observability platform. Traces every LLM call, evaluates outputs, manages datasets, and monitors production runs.

One-line integration for LLM cost and usage tracking. Proxy-based, works with any OpenAI-compatible API, caching support.

The leading ML experiment tracking platform, now with full LLM observability, prompts, traces, and evaluation.

Enterprise ML and LLM monitoring. Phoenix for OSS tracing, Arize for production monitoring - RAG evaluation built in.

Open-source LLM observability by Arize. Local traces, evaluation, embedding visualization - no cloud required.

Open-source LLM engineering platform. Traces, evaluations, prompt management, datasets - self-hostable or cloud.

OpenTelemetry-based LLM tracing. Integrates with existing observability stacks - Datadog, New Relic, Jaeger.

Comet's open-source LLM evaluation and tracing platform. RAG evaluation, hallucination scoring, LLM-as-judge.

LLM evaluation and observability platform focused on prompt engineering and A/B testing for production AI apps.

Real-time LLM monitoring and evaluation. Automated quality checks, guardrails, and regression testing for LLM apps.

LLM gateway with observability. Route traffic, cache responses, track costs, and get reliability with automatic retries and fallbacks.

Open-source OpenTelemetry-native LLM observability. One-line integration, GPU monitoring, cost tracking, Grafana dashboards.

LLM evaluation and testing platform. Write automated tests for prompts, version control prompts, track regressions.

Log, search, and analyze all your LLM requests. Built-in prompt registry, A/B testing, and visual prompt editor.