{
  "contract_name": "customer_registration_v1",
  "version": "1.0",
  "rules": {
    "customer_id": {
      "required": true
    },
    "age": {
      "required": true,
      "min": 18,
      "max": 110
    },
    "income_net": {
      "required": false,
      "min": 0,
      "missing_policy": "explicit_null"
    },
    "email": {
      "required": true,
      "regex": "^[^@\\s]+@[^@\\s]+\\.[^@\\s]+$"
    }
  }
}