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Payment Protocols

Agent payment protocols let autonomous systems prove intent, permissions, and constraints before money moves.

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Why Protocols Matter

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Supported Standards

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Supported Protocols

  • Visa TAP with RFC 9421
  • Google AP2 mandates
  • Mastercard VI SD-JWT

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ProtocolRouter

ProtocolRouter gives you a unified entry point for payment verification so each protocol can be normalized behind one decision surface.
protocol-router.ts
const verification = await protocolRouter.verify({
  protocol: request.protocol,
  headers: request.headers,
  body: request.body,
  featureFlags: {
    visaTap: true,
    googleAp2: true,
    mastercardVi: true,
  },
  fallback: "deny",
});

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Quick Comparison

ProtocolPrimary PrimitiveBest FitDelegation Model
Visa TAPHTTP signatures + noncesReal-time API authorizationKey-based agent identity
Google AP2Mandates + capabilitiesCheckout and shopping tasksMulti-hop narrowing chain
Mastercard VISD-JWT credentialsConstrained delegated paymentsL1 → L2 → L3 credential chain
Note: Recommendation: normalize all protocol outputs into one internal policy schema so fraud and limit engines stay protocol-agnostic.

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Explore by Protocol

  • visa-tap
  • ap2
  • mastercard-vi