What happens when VIES is temporarily unavailable?

vatnode first tries a national-registry fallback where one exists; if that can’t answer either, it returns HTTP 503 with VIES_UNAVAILABLE.

Why VIES goes down

VIES is shared infrastructure across 27 national tax authorities and has occasional outages, sometimes affecting just one country. The live status shows current VIES availability per country.

What vatnode does

• No requester VAT configured: vatnode first tries the national-registry fallback for supported countries, so many checks still get an answer while VIES is down. The coverage page lists which countries have a fallback at all.
• Check can’t be completed: if no fallback exists or it fails too, you get HTTP 503 with VIES_UNAVAILABLE.
• Requester VAT configured: the fallback is deliberately skipped to preserve the consultation number, so the 503 comes as soon as VIES fails.

A related error, UPSTREAM_TIMEOUT, means VIES said nothing at all within the timeout rather than reporting that it was down. In both cases no verdict was delivered, so nothing is counted against your quota.

How to handle it

VIES_UNAVAILABLE is very different from an ‘invalid’ result: the number may be perfectly valid, the EU system just couldn’t confirm it. Treat it as a signal to retry later rather than to reject the customer. For example, accept the order, mark the VAT number as pending verification, and re-run the check later. If you need results during an outage and don’t need consultation numbers, you can temporarily clear the requester in dashboard Account details.

The error reference documents this and every other error code in full.