EU VAT guides

Practical answers for when VAT number checks get complicated.

VIES error codes explainedWhat every VIES VAT validation error means — MS_UNAVAILABLE, MS_MAX_CONCURRENT_REQ, GLOBAL_MAX_CONCURRENT_REQ, INVALID_INPUT, TIMEOUT and more — and how to fix or work around each one.How to prove you checked a customer’s VAT numberA VIES consultation number is official proof that you verified an EU VAT number on a given date. Here’s how to get one, why it matters for the reverse charge, and how to store it for audits.VIES not working? What to do when it’s downVIES says "member state unavailable" or won’t load? See which countries are down right now, why it happens, and how to keep invoicing without risk.EU VAT number formats by countryThe format of the VAT number in every EU country and Northern Ireland: prefix, length, examples and local names. Free cheat sheet plus a live validator.VAT number valid but “invalid” in VIES?Your customer insists their VAT number is valid, but VIES says invalid. Here are the six most common reasons, including Spain’s ROI register and missing intra-EU activation.How to check a UK VAT number after BrexitGB VAT numbers are no longer in VIES. Here’s where to check them instead, and when Northern Ireland XI numbers can still be validated in VIES.How to check many EU VAT numbers at onceThe VIES website checks one VAT number at a time. Here’s how to validate a whole customer list from Excel or CSV, with names, addresses and consultation numbers.