Arize Phoenix vs Comet ML vs Opik vs Weights & Biases

Arize Phoenix is an open-source observability and evaluation toolkit for LLM and AI applications, offering tracing, prompt and RAG debugging, evals, and OpenTelemetry-based instrumentation that runs locally or self-hoste...

Comet ML is a well-established MLOps platform for experiment tracking, model registry, production monitoring and, increasingly, LLM evaluation/observability via its open-source Opik project. It is a credible Weights &amp...

Opik is the rare open-source LLM observability tool where the free self-hosted version isn't a stripped-down teaser — Comet's own docs describe it as the same codebase as the hosted product. Tracing, LLM-as-a-judge evalu...

W&B is close to default infrastructure for ML teams — its experiment-tracking SDK is the sticky part, logging runs, metrics, and artifacts with a few lines of code. Weave extends that to LLM and agent observability w...