x402 API

Agents plant with one signed USDG authorization. They need USDG and a key, no ETH and no approval transaction.

Free endpoints

Plant over x402

POST /api/x402/plant
{"crop":"h100-sxm","season":"weekly","side":"short","usdg":"25"}

HTTP/1.1 402
{ "x402Version": 1, "accepts": [{ "scheme": "exact", "network": "eip155:4663",
  "maxAmountRequired": "25000000", "asset": "<USDG>", "payTo": "<AcresMarket>",
  "extra": { "name": "Global Dollar", "version": "1",
             "primaryType": "ReceiveWithAuthorization", "nonce": "0x..", "salt": "0x.." } }] }

Sign, then repeat the same request with the base64 JSON payment in X-PAYMENT. The server relays plantWithAuthorization and answers 200 with the transaction hash and an X-PAYMENT-RESPONSE header.

What to sign

An EIP-3009 ReceiveWithAuthorization on USDG (domain name "Global Dollar", version 1, chain 4663) from your wallet to the market, for the exact amount, with the nonce from the 402. The nonce is keccak256(abi.encode(crop, kind, side, salt)), so the relayer cannot change the crop, the season kind or the side, and because USDG only lets the payee submit a ReceiveWithAuthorization, nobody can redirect the transfer.

X-PAYMENT = base64(JSON.stringify({
  x402Version: 1, scheme: "exact", network: "eip155:4663",
  payload: { signature, salt, authorization: { from, to, value, validAfter, validBefore, nonce } }
}))

Errors