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The VIES Consultation Number for Finance Teams

When an auditor reviews a zero-rated intra-EU invoice, one of the things they can ask is a simple question: how do you know the customer's VAT number was valid when you raised it? A screenshot of a VIES page from last week does not answer that. The VIES consultation number does — it is a reference the European Commission's system issues that ties a specific VAT number, a specific date and time, and a specific reply together. This guide is about why that reference matters to a finance, tax, or audit team, and what it does and does not prove. It is the business companion to the technical write-up on how to extract and store it — there is no code here.

The field auditors ask for

On a VAT audit of cross-border B2B supplies, the reviewer is testing whether you were entitled to not charge VAT. Part of that is substantive — was this genuinely a supply to a taxable person in another member state — and part of it is evidential: can you show you did the checks a diligent business is expected to do?

For the evidential part, self-produced records help but they are exactly that: self-produced. A line in your own system saying "checked, valid" is your word. The consultation number is different in kind. It is issued by VIES, not by you, and it points back to a validation that VIES itself performed. When Your Europe's guidance on checking a VAT number talks about proving to a tax administration that you checked a number and got a validation reply, the consultation number is the thing it tells you to keep. That is the whole reason it exists.

What the consultation number is, in plain English

VIES has two modes. A plain check answers "is this number valid, yes or no." A requester-qualified check answers the same question but records who was asking — you supply your own VAT number as the requester alongside the number you are checking. Only the requester-qualified check produces a consultation number.

Think of it as a receipt. It says: requester X asked VIES about number Y on date Z, and here is the reply. In the raw VIES response the value sits in a field called requestIdentifier — a short opaque string. You never need to read or interpret it; you store it as text and keep it with the transaction it relates to. That is the extent of what a finance team needs to know about its shape. If a single field reference is useful, it looks like this in a structured response:

{
  "valid": true,
  "consultationNumber": "WAPIAAAAX9999999",
  "verifiedAt": "2026-08-31T09:12:00Z"
}

The point is not the string. The point is that VIES attests to it.

Why it matters for zero-rated intra-EU B2B invoices

On an intra-EU B2B supply, the seller often does not charge local VAT — the supply may be a zero-rated intra-Community supply of goods, or the place of supply for a service may shift to the buyer under the reverse-charge mechanism. In both cases the buyer accounts for the VAT in their own country, and in both cases one of the conditions is that the buyer is a VAT-registered taxable person in another member state.

Verifying the buyer's VAT registration is therefore not a nicety, it is one of the things national authorities expect a seller to have done. The consultation number is the cleanest evidence that you did it, and that you did it at a point in time you can name. Where a plain screenshot proves nothing about when, the consultation number is contemporaneous — it is dated by the system that issued it. That is what makes it useful for an invoice you may have to defend years later.

Two clarifications keep this honest. First, the consultation number supports proof of verification; it is one input to the treatment, not the treatment itself. Second, whether validation is even required, and how often, depends on the situation — that is covered in when validation is required. If you want the plain-English picture of what VIES is before going further, what VIES is, for finance is the place to start.

What it does and does not prove

This is where the line has to be drawn precisely, because it is easy to claim too much.

What it proves:

• That you checked a specific VAT number.
• The date and time you checked it.
• The reply VIES gave.

What it does not prove:

• That the transaction is exempt or zero-rated. Those depend on substantive conditions — the nature of the supply, evidence of transport for goods, the buyer's status — not on the fact that a check happened.
• That the VAT number was "certified" or that the treatment is secured. The consultation number does not adjudicate the transaction. It is evidence you did your part of the diligence, nothing more.

So the accurate framing is narrow: keep the consultation number to prove that you checked, not to prove that the sale was correctly treated. It complements your own records; it does not replace them. If VIES was unreachable and a check fell through to another source, or if your client logged an attempt that never returned, those entries still belong in your trail — the consultation number just will not be on them.

What to keep alongside it

On its own the consultation number is a reference without context. To be usable as evidence, keep it next to the facts that give it meaning:

• The VAT number you checked, in the form you sent it.
• Your requester VAT number — the consultation number is meaningless without knowing who asked.
• The timestamp of the check.
• The reply — valid or not, and the trader name and address if returned.
• The source — was this answered by VIES, or by a national fallback source? Only VIES lookups carry a consultation number.
• The invoice or transaction the check belongs to, so the two can be tied together later.

That last link is what turns a pile of validations into an audit trail. A consultation number that you cannot connect to an invoice does not help anyone. Building the whole chain — check, evidence, invoice, retention — is its own exercise; there is a walkthrough in build the full audit trail.

Where it belongs in your records

A common question is whether the consultation number goes on the invoice itself. It does not have to, and no EU member state requires it to appear there. Some teams do print a short "VIES ref" near the customer's VAT number as a courtesy signal to the buyer's finance department, but that is a convention, not a legal invoice field. Treat it as internal evidence first.

Where it does belong is in your validation records, retained on the same footing as the invoice it supports. If your invoices are kept for a given period, the consultation numbers backing them should be kept at least as long — they are only useful for as long as the invoice they defend is open to review. Retention periods differ by jurisdiction, so the specific number of years is a question for your adviser, not for this page.

How to make sure you capture it every time

The consultation number is easy to lose without noticing, because a plain valid/invalid answer looks complete on its own. To capture it reliably:

• Run requester-qualified checks, not plain ones. If your validation path does not send a requester VAT number, VIES will answer the question but issue no consultation number. There is nothing to store after the fact — you either asked for it at the time or you did not.
• Persist it immutably. Append each check as a new record; never overwrite an earlier one with a later result. The evidence is time-specific, and overwriting destroys it.
• Allow it to be absent. When a check is answered by a national fallback source instead of VIES, there is no consultation number, and that is expected. Keep the record anyway, mark the source, and leave the reference blank rather than inventing one.

If you would rather not manage the VIES call and its edge cases yourself, a VIES API that returns the consultation number does the requester-qualified lookup on every live check and hands you the field as structured data — the mechanics of extracting and storing it are in how to extract and store it. You can run a check to see the consultation number a live lookup returns.

This is general information about EU VAT and VIES, not tax advice — whether and how to rely on the consultation number for a specific filing is for a qualified adviser.

FAQ

What is a VIES consultation number?

It's the reference VIES issues for a requester-qualified validation — proof that you checked a specific VAT number at a specific time and what reply you got. The Commission's guidance is to keep it in your records as evidence you ran the check.

Is the consultation number unique to vatnode?

No. VIES issues it; any provider that runs a requester-qualified check can return it. It is a standard part of the VIES response, not something exclusive to one service.

Is a consultation number returned for every check?

No. It exists only for requester-qualified VIES lookups. A check answered by a national fallback source has no consultation number, so don't assume it's always present.

How long should we keep it?

Align it with your invoice retention — the consultation number backs up the invoice it relates to. Retention periods vary by jurisdiction; this is general information, not tax advice.

Capture the consultation number on every check

vatnode runs requester-qualified VIES checks — set your EU VAT number once in Settings and every live VIES check then returns the consultation number as a structured field, so your finance records carry the evidence without extra work. Free plan, 100 requests/month.

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