EU-momsnummer-validator (VIES)

Inside the European Union, the reverse-charge mechanism for B2B cross-border supplies is one of the most powerful simplifications in the VAT framework. It lets businesses sell to customers in other EU countries without charging VAT, leaving the customer to self-account in their home country. The simplicity comes with a strict condition: the customer's VAT identification number must be valid and currently active at the time of supply. If the seller fails to verify the number and the customer turns out not to be VAT-registered, the seller becomes liable for the VAT they did not charge — plus penalties.

VIES (VAT Information Exchange System) is the official European Commission service for verifying that a VAT number is currently registered in a member state's tax registry. It is free, requires no API key and is the only verification method that EU tax authorities accept as proof of due diligence. Many member states (including Germany, France and Italy) explicitly require sellers to keep VIES validation records on file for any reverse-charge invoice. A missing record is one of the most common findings during a VAT audit.

WorkDaten's VAT validator runs the live VIES check from your browser via our server, returning the trader name and address where the member state allows it. The validation is recorded with the request date so you can copy the receipt directly into your accounting notes. When you build an invoice afterwards, the verified data carries over to the invoice generator with one click, eliminating the typo risk that comes with re-typing a long alphanumeric VAT number on each new invoice.