VAT Numbers Explained for Online Sellers
A VAT number is a registration, not a promise
The number identifies a business registered with its national tax authority. It proves nothing about the deal you are about to make — only that the entity can legally charge and reclaim VAT. Registration status changes; a number valid last year may be revoked today.
When the reverse charge applies
Intra-EU B2B sales normally shift VAT accounting from the seller to the buyer — but only when both sides have valid registrations and the invoice states it. Get either wrong and the liability lands on the seller. This is why serious sellers validate every new client number at VIES (the European Commission's live check) rather than trusting a PDF someone emailed them.
The pre-invoice checklist
Format matches the country pattern → live validation passes → the registered name roughly matches your counterparty → log the validation result with a timestamp. Four steps, two minutes, and the difference between clean books and an assessment notice.