Arize Phoenix

Open-source LLM tracing and eval.

Visit site GitHub
Open source Self-hostable free
LicenseElastic-2.0
Starting priceSelf-host free
Model supportmulti
Languagespython, typescript
GitHub stars10.3k
Last activity2026-06-25
VerifiedThu Jun 25 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
Verified byseed

An open-source observability and eval tool built on OpenTelemetry, with strong tracing and LLM-as-a-judge evals.

Strengths

  • Open source with OTel foundations
  • Good LLM-as-a-judge evals built in

Tradeoffs

  • Elastic license restricts some hosted offerings
  • Enterprise features in the paid Arize cloud