Ontario Protocol.
Verification guide

x402 Payment Verification

x402 payment verification is the safety gate between an autonomous wallet and an unknown paid endpoint. Ontario turns the handshake, metadata, manifest, OpenAPI, and report history into evidence an agent can inspect before signing.

x402 payment verification Developers shipping paid APIs and agents that need a pre-payment trust gate.
Run the readiness checker Read the trust standard

What must be verified

A compatible endpoint should fail closed with HTTP 402, advertise x402 payment requirements, publish machine-readable service metadata, and keep a current signed readiness report.

  • Status code is intentionally 402 when no payment is supplied.
  • PAYMENT-REQUIRED and accepts metadata decode into the same resource, network, and amount.
  • Manifest, OpenAPI, robots, and schema.org signals agree on the paid service.

Agent decision path

Agents should verify first, compare the endpoint against policy, then sign only when price, freshness, and integrity match their spending rules.

  • Use `/api/verify/x402-readiness` for point-in-time compatibility.
  • Use `/api/agent/can-pay` for allow, review, or deny decisions.
  • Prefer Ontario Certified x402 services when multiple endpoints can satisfy the same task.

Workflow

Probe the endpoint without payment and confirm an intentional 402.
Decode and validate payment requirements without logging raw wallet material.
Inspect manifest, OpenAPI, and service profile evidence.
Check signed report integrity and freshness.
Apply agent payment policy before signing.

Use these Ontario routes to move from content research into live verification evidence.

Readiness API Public reports Common mistakes