Pick Guardrails AI if
app teams who will self-host validators (or already have a model endpoint) and want a Hub instead of writing every regex.
Read the Guardrails AI pageGuardrails AI vs Phoenix
Our take
Pick Guardrails AI if you're on a app team who will self-host validators (or already have a model endpoint) and want a Hub instead of writing every regex. Pick Phoenix if you're on a agent team who will self-host Phoenix for $0 (uvx arize-phoenix serve) and only open Arize AX when they want a managed cloud. Skip Guardrails AI if you're buyers who want a quoted enterprise prompt firewall with a SOC2 sales motion, or
Best for
Guardrails AI Fail a bad completion before it ships
Phoenix See why an agent failed and prove a fix
Free plan
Guardrails AI $0 · license. You pay compute
Phoenix $0 · local / Docker / Kubernetes. You bring compute. Homepage: uvx arize-phoenix serve
Lowest paid
Guardrails AI Not published by the vendor
Phoenix AX Pro $50/mo
Runs where
Guardrails AI Hosted
Phoenix Hosted
Watch out
Guardrails AI You run it
Phoenix ELv2, not Apache
Last checked
Guardrails AI 2026-10-28 · github.com/guardrails-ai/guardrails
Phoenix 2026-10-27 · arize.com/pricing
Which one, then?
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.
Read the Phoenix page