curl --request POST \
  --url https://api.example.com/x402/verify \
  --header 'Content-Type: application/json' \
  --data '
{
  "paymentHeader": "<string>",
  "paymentRequirements": "<unknown>",
  "x402Version": 1
}
'

{
  "isValid": true,
  "invalidReason": "<string>"
}