Question 1

What is VIES?

Accepted Answer

VIES (VAT Information Exchange System) is the European Commission's official service for verifying VAT identification numbers issued by EU member states. It confirms whether a VAT number is currently valid and, for most countries, returns the registered business name and address.

Question 2

Why should I validate a VAT number before invoicing?

Accepted Answer

For cross-border B2B sales within the EU you can usually zero-rate the invoice (reverse charge), but only if your customer has a valid VAT number on the day of supply. Validating with VIES protects you from being held liable for the missing VAT during a tax audit.

Question 3

Which countries are supported?

Accepted Answer

All 27 EU member states plus Northern Ireland (XI prefix). Greek VAT numbers use the EL prefix, not GR. Non-EU countries (UK, Switzerland, Norway, etc.) are not part of VIES — use their national tax authority instead.

Question 4

Why does VIES sometimes return 'service unavailable'?

Accepted Answer

VIES queries each member state's database in real time. National systems occasionally go offline for maintenance, especially evenings and weekends. Wait a few minutes and try again — your invoice is still valid if the number was confirmed on a previous successful check.

EU VAT Number Validator

How VAT number validation works

FAQ