curl --request POST \
  --url https://api.httpayer.com/relay/sim \
  --header 'Content-Type: application/json' \
  --data '
{
  "api_url": "https://demo.httpayer.com/base-weather",
  "method": "GET",
  "payload": {},
  "params": {},
  "headers": {
    "X-API-KEY": "your-target-api-key",
    "Authorization": "Bearer token123"
  },
  "network": "base"
}
'

{
  "requiresPayment": true,
  "targetPaymentRequirements": {
    "scheme": "exact",
    "network": "base",
    "payTo": "<string>",
    "asset": "<string>",
    "maxAmountRequired": "<string>",
    "resource": "<string>",
    "description": "<string>",
    "mimeType": "application/json",
    "maxTimeoutSeconds": 180
  },
  "relayFeeBreakdown": {
    "targetAmount": 123,
    "relayFee": 123,
    "totalAmount": 123,
    "relayFeePercentage": 3,
    "relayFeeMinUSDC": 0.002,
    "feeModel": "3% with $0.002 minimum"
  },
  "message": "<string>"
}