Principle
How it works
The VAT number is checked on both sides of the address form: in the browser for instant feedback, and on the server, the only truly reliable barrier.
- Company entered, number empty
The address is refused with « The VAT number is required when a company is provided ». As an option, this rule only applies in the EU: a US or Swiss company can order without a number.
- Format and VIES
The number must follow its country's official format (EU countries, United Kingdom); in the EU, it can also be checked with the European VIES service.
- Foreign business
A billing address in another country with a valid VAT number is invoiced without VAT, from cart to invoice. The invoice reads « Reverse charge » (EU customer) or « Supply not taxable in the EU » (non-EU customer).
- Country reserved for businesses
In a chosen country (the United Kingdom, for instance), the company and the number are mandatory; a consumer cannot pay and a message explains why.
No company, no constraint — except in countries reserved for businesses. The number is then neither required nor checked, and the field can be hidden.