Arize Phoenix
ELv2 self-host AI observability & eval — traces, datasets, playground
AI Agents / Agents · Open-Core · 11.9k
Reviewed 2026-09-29 · last push 2026-10-18 · repo checked 2026-10-19
What's Good
Elastic License 2.0 (Arize-ai/phoenix). Open inference tracing, embeddings viz, datasets, experiments, and eval helpers; pip/Docker self-host; pairs with Arize AX cloud if you outgrow local. Docs at arize.com/docs/phoenix. ★11,645 on GitHub 2026-09-29.
The Catch
NOT OSI open source — ELv2 forbids offering Phoenix as a competing hosted SaaS. Vs Langfuse (MIT full-stack self-host) and Braintrust (eval-first freemium): Phoenix is Arize’s ELv2 observability/eval kit with strong notebook/embedding UX, not MIT and not Braintrust’s CI-eval product. Arize cloud is the upsell when you want managed multi-tenant.
Verdict
ELv2 self-host AI obs/eval when Phoenix’s tracing+evals fit and you accept source-available — not Langfuse MIT, not Braintrust CI-eval.
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