About VIES EU VAT validation
The official EU service that says this VAT number is real, today.
VIES (VAT Information Exchange System) is the European Commission's public service for checking whether a VAT number is valid for intra-EU transactions. A request goes out to the issuing member state's own database in real time and comes back with a yes or no, the trader name and address where that member state shares them, and a consultation number that proves the check happened.
The service is reachable from the public Vies-on-the-Web page, the SOAP checkVatService endpoint that ERPs and accounting tools have used for years, and a more recent REST endpoint. It covers the 27 EU member states. The European Commission is explicit that VIES does not store the data itself and is not responsible for accuracy: the answer is only as fresh as the national tax authority's own database. That is exactly why the consultation number matters. It is the audit-grade proof that on a given date, that VAT number was valid according to the home country's records.