Our take
Pick Arize AX if agent / ML teams who will stay on AX Free at $0 (10 Signal issues, 25k spans, 1 GB, 15-day retention) while they open a first Signal list, then AX Pro at $50/month when they need 25 issues, 50k spans, or 30-day retention. Pick Phoenix if agent teams who will self-host Phoenix for $0 (uvx arize-phoenix serve) and only open Arize AX when they want a managed cloud.
Best for
Arize AX An issue list you start at a public $
Phoenix See why an agent failed and prove a fix
Free plan
Arize AX $0 · no card. 10 Signal issues / month. 25k trace spans / month. 1 GB ingestion. 15-day retention. SaaS. Unlimited users. Unlimited evals. 1 org / 1 space
Phoenix $0 · local / Docker / Kubernetes. You bring compute. Homepage: uvx arize-phoenix serve
Lowest paid
Arize AX AX Pro $50/mo
Phoenix AX Pro $50/mo
Coding agent
Arize AX Experiments
Phoenix
Runs where
Arize AX Local or hosted
Phoenix Hosted
Watch out
Arize AX Free Signal caps at 10 issues / month (account-wide, UTC)
Phoenix ELv2, not Apache
Last checked
Arize AX 2026-10-23 · arize.com/pricing
Phoenix 2026-10-22 · arize.com/pricing
agent / ML teams who will stay on AX Free at $0 (10 Signal issues, 25k spans, 1 GB, 15-day retention) while they open a first Signal list, then AX Pro at $50/month when they need 25 issues, 50k spans, or 30-day retention.
Read the Arize AX pageagent teams who will self-host Phoenix for $0 (uvx arize-phoenix serve) and only open Arize AX when they want a managed cloud.
Read the Phoenix page
