curl --request POST \
  --url https://api.neynar.com/v2/signature/x402/ \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --header 'x-wallet-id: <x-wallet-id>' \
  --data '
{
  "payment_requirements": {
    "accepts": [
      {
        "asset": "0x5a927ac639636e534b678e81768ca19e2c6280b7",
        "description": "<string>",
        "maxAmountRequired": "<string>",
        "maxTimeoutSeconds": 123,
        "payTo": "0x5a927ac639636e534b678e81768ca19e2c6280b7",
        "resource": "<string>",
        "extra": {},
        "mimeType": "<string>",
        "outputSchema": {}
      }
    ]
  }
}
'

{
  "payload": {
    "authorization": {
      "from": "0x5a927ac639636e534b678e81768ca19e2c6280b7",
      "nonce": "<string>",
      "to": "0x5a927ac639636e534b678e81768ca19e2c6280b7",
      "validAfter": "<string>",
      "validBefore": "<string>",
      "value": "<string>"
    },
    "signature": "<string>"
  }
}