castomAPI
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POST /v1/verify/vat 1 token API key Verify

Verify EU VAT identification numbers

Verify EU VAT identification numbers via official European Commission VIES database. Validates structural syntax, country matching, company identity, and audit consultation codes

POST

Request

  • x-api-key: <your-api-key>
  • Content-Type: application/json

Response

{
  "status": "success",
  "valid": true,
  "countryCode": "PL",
  "vatNumber": "8993033031",
  "name": "CASTOMO PROSTA SPÓŁKA AKCYJNA",
  "address": "UL. POWSTAŃCÓW ŚLĄSKICH 5/212, 53-332 WROCŁAW",
  "requestDate": "2026-09-08",
  "source": "VIES",
  "tokensDeducted": 1
}
The response below is a mock built from the endpoint's own schema — no request leaves this page. Edit the body, press Send, read the shape you will get back. Run it for real in the dashboard →

What it does

Checks an EU VAT number against the European Commission's VIES service and returns what the member state registry holds: validity, the registered name and the registered address. The country prefix is read from the number. VIES itself is intermittently unavailable per member state; when it is, the endpoint answers a 502 that is not billed rather than a guess.

When to use it

B2B checkout before issuing a reverse-charge invoice; supplier onboarding; cleaning a CRM.

Request

Body

FieldTypeRequiredDescription
countryCodestringnoOptional 2-letter ISO country code if not included in vatNumber string (e.g. "PL", "DE", "GR")
requesterVatNumberstringnoOptional requester VAT number to obtain an official EU audit consultation reference number
vatNumberstringyesThe VAT number to verify (e.g., "PL1234567890", "DE 123456789", or "123456789")

Example request

{
  "vat": "PL8993033031"
}

Response

FieldTypeDescription
auditEvidenceobject
  ↳ consultationNumberstring
  ↳ requestDatestring
companyDetailsobject
  ↳ addressstring
  ↳ citystring
  ↳ namestring
  ↳ postalCodestring
  ↳ streetstring
isValidboolean
statusstring
tokensDeductedinteger
validationResultobject
  ↳ isFormatValidboolean
  ↳ isViesRegisteredboolean
  ↳ reasonstring
  ↳ viesStatusstring
vatDetailsobject
  ↳ cleanVatNumberstring
  ↳ countryCodestring
  ↳ countryNamestring
  ↳ isEuMemberboolean
  ↳ nationalNumberstring
  ↳ rawInputstring

Example response

{
  "status": "success",
  "valid": true,
  "countryCode": "PL",
  "vatNumber": "8993033031",
  "name": "CASTOMO PROSTA SPÓŁKA AKCYJNA",
  "address": "UL. POWSTAŃCÓW ŚLĄSKICH 5/212, 53-332 WROCŁAW",
  "requestDate": "2026-09-08",
  "source": "VIES",
  "tokensDeducted": 1
}

Errors

Every error answers with the same envelope: an HTTP status, a machine code and a sentence.

400The body or a parameter failed validation. The details array names the field.
401No key, a revoked key or a wrong header. Send x-api-key.
402The wallet cannot cover this call. Top up or wait for the monthly grant.
404The resource does not exist, or it is not yours. Both answer identically and cost nothing.
429Over the per-minute quota of your tier. Back off and retry.
5xxUpstream refused or timed out. The call is not billed.

Code

curl -X POST 'https://app.castomapi.com/v1/verify/vat' \
  -H 'x-api-key: <your-api-key>' \
  -H 'Content-Type: application/json' \
  -d '{"vat": "PL8993033031"}'
const res = await fetch('https://app.castomapi.com/v1/verify/vat', {
  method: 'POST',
  headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
  body: JSON.stringify({"vat": "PL8993033031"})
});
const data = await res.json();
console.log(data);
import { request } from 'node:https';

// Node 18+ has fetch built in
const res = await fetch('https://app.castomapi.com/v1/verify/vat', {
  method: 'POST',
  headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
  body: JSON.stringify({"vat": "PL8993033031"})
});
const data = await res.json();
console.log(data);
import requests

res = requests.post(
    'https://app.castomapi.com/v1/verify/vat',
    headers={'x-api-key': '<your-api-key>'},
    json={"vat": "PL8993033031"},
    timeout=30,
)
print(res.json())
<?php
$ch = curl_init('https://app.castomapi.com/v1/verify/vat');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['x-api-key: <your-api-key>', 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS => json_encode(['vat' => 'PL8993033031']),
]);
$data = json_decode(curl_exec($ch), true);
print_r($data);

Cost and limits

This operation costs 1 token. A call that fails is never billed. Every account gets 1000 free tokens a month; paid balances never expire.

Rate limits per minute

No key10
Free60
Pro300
Enterprise1200

Docs → Pricing

Questions

What does Verify EU VAT identification numbers cost?

1 token per successful call, debited from your wallet after the response. Failed calls are free. Every account receives 1000 free tokens a month.

How do I authenticate?

Send your key in the x-api-key header. One key covers every metered endpoint; there is nothing to enable per endpoint.

Can I send an Authorization: Bearer token instead?

Not for a metered endpoint — those take the x-api-key header and nothing else. Bearer tokens belong to the account side: the dashboard and account APIs accept a JWT session, and castomapi-auth issues those through a standard OAuth2 handshake, with authorization code, client credentials and refresh grants. The auth service page covers it.

What are the limits?

10 requests a minute per IP with no key at all, 60 a minute on the free tier, 300 on Pro, 1200 on Enterprise. Above the no-key tier the quota is per account, across every endpoint.

OpenAPI: https://app.castomapi.com/docs/json