Our take
Pick Arize AX if you're on a agent / ML team 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 Evidently if you're on a mL / LLM team who will run Evidently locally at $0 — not Arize first unless they want hosted Signal at $50.
Best for
Arize AX An issue list you start at a public $
Evidently One Apache dashboard for LLM and classic ML quality
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
Evidently $0 · local UI (evidently ui). You bring compute and judge-model keys
Lowest paid
Arize AX AX Pro $50/mo
Evidently Not published by the vendor
Coding agent
Arize AX Experiments
Evidently
Runs where
Arize AX Local or hosted
Evidently Hosted
Watch out
Arize AX Free Signal caps at 10 issues / month (account-wide, UTC)
Evidently $0 is the library, not judge tokens
Last checked
Arize AX 2026-10-23 · arize.com/pricing
Evidently 2026-10-27 · evidentlyai.com
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 pagemL / LLM teams who will run Evidently locally at $0 — not Arize first unless they want hosted Signal at $50.
Read the Evidently page
