This service uses VIES VAT number validation. It returns

{
  "countryCode": "DE",
  "vatNumber": "DE1234567",
  "requestDate": "2019-04-04T06:03:30.889Z",
  "valid": true,
  "name": "company name", // if provided by the database, otherwise "---"
  "address": "company address" // if provided by the database, otherwise "---"
}

when the request is valid and

{
    "countryCode": "DE",
    "vatNumber": "DE1234567",
    "requestDate": "2019-04-04T06:03:30.889Z",
    "valid": false,
    "name": "---",
    "address": "---",
    "error": "The provided CountryCode is invalid or the VAT number is empty"
}

when the request is invalid.