Arize Phoenix (arize-phoenix)

Open-source AI observability and evaluation platform from Arize AI. Phoenix provides tracing, evaluation, prompt management, datasets, and experiments for LLM applications. Built on OpenTelemetry and OpenInference. Can be run locally, self-hosted (Docker/K8s), or accessed via cloud at app.phoenix.arize.com. CRITICAL: Phoenix is a separate product from Arize AX (the enterprise cloud platform). They share the Arize brand but use different packages, credentials, and endpoints: Phoenix uses phoenix.otel + PHOENIX_API_KEY; Arize AX uses arize.otel + ARIZE_SPACE_ID + ARIZE_API_KEY. arize-phoenix is the full-platform bundle. For production deployments, the modular sub-packages (arize-phoenix-otel, arize-phoenix-client, arize-phoenix-evals) are preferred. LICENSE: Elastic License 2.0 (ELv2) — NOT MIT/Apache. Restrictions apply to providing Phoenix as a managed service to third parties.