EU VAT Validator (VIES): Verify & Bulk-Check VAT IDs

Validate any EU VAT number — plus Northern Ireland (XI) — straight against the official, free VIES (VAT Information Exchange System) service. Get a real valid/invalid answer, the registered company name and address when the country exposes them, and bulk-check up to 100 VAT IDs in one call.

An MCP server hosted on MCPize. Also published as an Apify Actor with the same VIES core.

What it does

EU VAT Validator checks any EU (or Northern Ireland) VAT number against the live European Commission VIES service and tells you three things a naive checker can't: whether the number is currently valid, the registered business name and address when the member state publishes them, and — critically — whether a failed check means the number is genuinely invalid or the member state's own system is just temporarily unavailable. Most VAT checkers collapse those last two into one generic "failed" result. This one doesn't, because for compliance and invoicing decisions the difference matters.

Who it's for: finance and AP/AR teams validating VAT numbers on invoices, e-commerce and marketplace platforms doing reverse-charge B2B checks at checkout, onboarding/KYB teams verifying a new business customer or supplier, and AI agents that need a VAT-validation step inside a larger workflow.

Related MCP server: vies-smoother

Why it's built this way

• Official VIES data, not a guess — every check hits the European Commission's own VIES REST API. No scraping, no third-party VAT number checker database, no stale cache.

• Free, no API key — VIES is a free public EU service and this server needs no credentials to use it.

• Company name & address lookup — when a member state publishes it, validate_vat returns the registered business name and address, not just true/false.

• Down vs. invalid, correctly separated — VIES member states go offline often. This tool reads VIES's own error codes so MS_UNAVAILABLE (retry later) is never confused with INVALID (the number doesn't exist).

• Bulk-ready — check up to 100 VAT IDs in one call, processed 5-at-a-time so one slow member state never stalls the batch, with a pass/fail summary.

• EU + Northern Ireland (XI) — covers all 27 EU member states plus the XI prefix used for Northern Ireland VAT numbers post-Brexit.

• Nothing stored — VAT IDs and results are never logged or retained beyond the response.

VIES vs. a manual VAT check

Checking a VAT number by hand on the official VIES web page works for one number at a time, gives you no structured output, and gives no way to tell "invalid" apart from "the site's timing out again." This server wraps the same official VIES REST API an AI agent or app can call directly — structured JSON in, structured JSON out, with the invalid/unavailable distinction VIES's own website doesn't surface — and does 100 numbers as easily as one.

Who it's for

For finance teams. Before filing a VAT return, check the customer VAT column and get a per-number valid / invalid / temporarily-unavailable verdict, so a zero-rated intra-EU sale is defensible if the return is queried.

For accountants. Re-check a client's supplier ledger each quarter and catch numbers deregistered since onboarding — the ones that fail an audit two years later, not today.

For developers and AI agents. Call validate_vat inside an onboarding flow, branch on the three states, and escalate to a human only when VIES says the number is genuinely invalid.

When to use it, and when not to

Use it to confirm a VAT number is registered for intra-EU trade, to bulk-clean a customer or supplier list, and to obtain a consultation number as audit evidence.

Do not use it to determine VAT treatment. A valid result confirms registration, not entitlement to any particular rate or relief, and it is not tax advice. It does not cover Great Britain (GB) numbers, which are not in VIES.

Use cases

• Invoicing — confirm a customer's VAT number before you issue a zero-rated intra-EU invoice.

• Reverse-charge B2B — verify the buyer's VAT ID at checkout to correctly apply (or withhold) reverse-charge VAT treatment.

• Onboarding / KYB — check a new business counterparty's VAT registration and registered address as part of know-your-business checks.

• Bulk customer-list cleaning — run a CRM or billing export through bulk_check_vat to find dead, mistyped, or deregistered VAT numbers.

Tools

validate_vat

Verify one EU/XI VAT number against VIES; returns validity, company name/address, and a status that separates invalid from temporarily-unavailable.

Example call:

{ "vat_id": "IE6388047V" }

Example output:

{
  "input": "IE6388047V",
  "countryCode": "IE",
  "vatNumber": "6388047V",
  "valid": true,
  "status": "VALID",
  "businessName": "GOOGLE IRELAND LIMITED",
  "businessAddress": "3RD FLOOR, GORDON HOUSE, BARROW STREET, DUBLIN 4",
  "requestDate": "2026-07-22T19:36:51.094Z",
  "consultationNumber": null
}

bulk_check_vat

Verify up to 100 VAT numbers in one call, processed 5-at-a-time; returns one result per id plus a pass/fail summary. A single bad id never fails the batch.

Example call:

{ "vat_ids": ["IE6388047V", "DE811569869", "FRXX999999999"] }

Output: { results: [ per-id objects shaped like validate_vat ], summary: { total, valid, invalid, invalid_input, unavailable } }.

check_vies_status

Report each EU member state's current VIES availability, so you can tell whether an MS_UNAVAILABLE result is worth retrying right now. Takes no input.

Example call:

{}

FAQ

How do I know if a VAT number is valid? Call validate_vat with the full number including its country prefix (e.g. IE6388047V). It returns valid: true/false plus a status field — check status, not just valid, since a false result can also mean the check couldn't complete.

Can I bulk validate a list of VAT numbers? Yes — bulk_check_vat accepts up to 100 VAT IDs per call and checks them 5 at a time. For larger lists, split into batches of 100.

What if VIES is down or a member state isn't responding? You'll get status: "MS_UNAVAILABLE" (that specific country's system is down) or "SERVICE_UNAVAILABLE" (VIES itself is unreachable) instead of a false "invalid." Call check_vies_status to see which countries are currently reachable before retrying.

Does it return the company name? Yes, when the member state publishes it via VIES — businessName and businessAddress come back on a valid check. Some member states don't expose this data through VIES; in that case both fields are null even though the number is valid.

Does it work for UK VAT numbers? Only Northern Ireland (XI) numbers — the rest of the UK left VIES after Brexit and isn't covered by this or any VIES-based tool.

Do I need an API key? No. VIES is a free official EU service and this server calls it directly with no credentials.

Trust & compliance

Checks against the official European Commission VIES service only — no third-party VAT database, no scraping, no aggregation. Nothing is stored: VAT IDs and results are never logged or retained beyond the response. This is a verification aid, not legal or tax advice — the compliance decision is yours.

Configuration (optional)

requesterVatId — your own EU VAT number. When set, it's sent to VIES as the requester identity so every response includes an official consultationNumber (a proof-of-check reference useful for audit trails). Leave it unset and everything else works exactly the same.

Using this from an AI agent (MCP)

// validate_vat
{ "vat_id": "IE6388047V" }

// bulk_check_vat
{ "vat_ids": ["IE6388047V", "DE811569869"] }

// check_vies_status
{}

Local development

npm install
npm run dev     # http://localhost:8080/mcp, hot reload
npm test        # vitest
npm run build   # tsc

Deployment

mcpize login
mcpize deploy
mcpize publish --show

License

MIT