x402 Checker

Check whether a site advertises x402, the HTTP 402-based payment protocol for agents.

Probes /.well-known/x402.json for discovery metadata. x402 revives the long-unused HTTP 402 Payment Required status so an agent can pay for a resource programmatically. It is only meaningful for a site that sells something an agent can buy.

This is one of the checks the AI Agent Readiness Checker scores under Agentic Commerce, and it can also be run on its own for any URL.

Experimental · Based on: x402 — HTTP-native payment protocol

About this validation

Experimental / emerging convention

Probes for x402 discovery metadata. x402 is an emerging HTTP 402-based payment protocol for agent-initiated transactions, stewarded outside any formal standards body.

Protocol / standard:: x402 — HTTP-native payment protocol(draft, not yet ratified)
Rules reviewed:: Nov 11, 2026

Standards and vendor-documented behavior can change. This reflects the source as last reviewed above, not a permanent guarantee.