How AI agents pay APIs with x402

AI agents pay APIs using x402 by making a normal HTTP request, receiving a 402 response containing payment requirements (network, asset, amount, payTo address), signing a stablecoin transfer with their wallet, and retrying with the signed payload in an X-PAYMENT header. is-real-biz implements x402 v1 end-to-end: every paid endpoint (/check, /check_batch) returns structured 402 envelopes, verified and settled through the PayAI facilitator on Base / Base Sepolia.

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curl 'https://is-real-biz.is-real-biz.workers.dev/check?domain=stripe.com'

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Step-by-step

1. Agent sends the request. GET /check?domain=stripe.com (no auth)
2. Server returns 402. Response body lists scheme=exact, network=base-sepolia, asset=USDC, payTo=0x..., maxAmountRequired=50000 (5¢)
3. Agent signs USDC transfer. Using a client like wrapFetchWithPayment(fetch, signer) the agent crafts an EIP-3009 transferWithAuthorization, base64-encodes it, attaches X-PAYMENT header.
4. Server verifies + settles. is-real-biz POSTs to facilitator.payai.network/verify and /settle. On success the verdict is returned plus an X-PAYMENT-RESPONSE header with the settlement receipt.

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