What is the VIES consultation number, and do I need it?

It’s the requestIdentifier VIES returns for one specific check – the official EU-side reference you can keep as evidence that the check was made, alongside an invoice that applied reverse charge.

What it proves, and what it doesn’t

The consultation number documents that a particular requester checked a particular VAT number at a particular point in time, through the official EU system. On its own it does not establish zero-rate or reverse-charge entitlement, and it is not a legal safe harbour. What an authority expects differs by member state – Germany, for instance, runs its own qualified confirmation procedure through the BZSt, which is a separate request from this one. Confirm your obligations with a tax adviser.

How you get it

It’s opt-in. vatnode returns it only once you set your own EU VAT number as the requester in dashboard Account details, because the identifier is issued against your VAT, not vatnode’s – a check run under vatnode’s own VAT would be worthless as evidence for your invoice. Once it’s set, there is nothing to change in your calls:

• GET /v1/vat/DE811257210 returns consultationNumber in the response, for example WAPIAAAAW21qsOHW.
• There is no per-request parameter and no per-call override – the setting applies to every check on the account.
• With a requester set, vatnode skips its cache and the national-registry fallback, so the outcome is binary: a result that carries a consultation number, or an error (VIES_UNAVAILABLE or INVALID_REQUESTER).

Do you need it?

You don’t strictly need it for everyday, non-audit validation. Without a requester configured, every response still includes a checkId and a verifiedAt timestamp, but those are vatnode’s own internal reference for the call – useful for looking a specific check up with support, not evidence by themselves.

If you apply reverse charge to EU B2B invoices, store the consultationNumber, verifiedAt and the validated company name next to the invoice. Check records are kept for five years and then anonymised, and retention obligations vary by country, so keep your own archive too. See the VAT audit trail guide for the full picture, including how retention requirements vary by country, and the validation endpoint reference for the response fields.