Integrate Skyfire KYAPay at a merchant API endpoint so it accepts and validates agent KYA tokens for identity and payment authorization

Steps

1. Register your service in the Skyfire developer portal and obtain an API key; configure the token verification public keys from the Skyfire JWKS endpoint
2. At your API entry point, inspect the incoming Authorization or X-KYAPay-Token header for a KYAPay JWT signed by the buyer agent's authorization server
3. Decode the JWT and validate signature, expiry, audience, and scopes against Skyfire's JWKS; reject with HTTP 401 if invalid or expired
4. Extract the KYA identity claims (agent DID, principal, trust level) and the embedded payment credential; confirm the payment amount and currency match the requested resource price
5. If valid, fulfill the request and return the resource along with an X-KYAPay-Receipt header containing a signed confirmation JWT for the buyer's audit trail
6. Log the transaction with the KYAPay token fingerprint, timestamp, and settlement reference for reconciliation