A agentindex
Comparison

Arize Phoenix vs Comet Opik

A like-for-like, spec-level comparison. Both entries are verified against their docs and repo.

Arize Phoenix

Open-source LLM tracing and eval.

  • + Open source with OTel foundations
  • + Good LLM-as-a-judge evals built in
  • − Elastic license restricts some hosted offerings
  • − Enterprise features in the paid Arize cloud

Comet Opik

Open-source eval and tracing from Comet.

  • + Open source with self-host option
  • + Backed by Comet's MLOps experience
  • − Smaller community than Langfuse
  • − UI less polished than paid rivals
Spec Arize Phoenix Comet Opik
Category eval-observability eval-observability
License Elastic-2.0 Apache-2.0
Open source Yes Yes
Self-hostable Yes Yes
MCP support No No
Pricing free freemium
Starting price Self-host free Self-host free
Models multi multi
Languages python, typescript python, typescript
GitHub stars 10.3k 19.8k
Last activity 2026-06-25 2026-06-25