The EU VAT Number Validation API can be accessed via a GET request and accepts the following parameters:

vat (required): The full VAT number including the country code.
country (required if vat is not provided): The two-letter country code in uppercase.
vatnum (required if vat is not provided): The VAT number without the country code.
Example usage: GET https://your-api-endpoint.com/validate?vat=IE6388047V or GET https://your-api-endpoint.com/validate?country=IE&vatnum=6388047V

The API will return a JSON object containing the validation status and the company details if the VAT number is valid. The object will contain the following fields:

valid: Boolean indicating if the VAT number is valid or not.
name: The name of the company.
address: The address of the company.
countryCode: The two-letter country code.
vatNumber: The VAT number.
Note: Please make sure that you pass only the parameters that are required to validate the VAT number. If both vat and country + vatnum are provided, only vat will be considered.