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
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
}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
| Field | Type | Required | Description |
|---|---|---|---|
countryCode | string | no | Optional 2-letter ISO country code if not included in vatNumber string (e.g. "PL", "DE", "GR") |
requesterVatNumber | string | no | Optional requester VAT number to obtain an official EU audit consultation reference number |
vatNumber | string | yes | The VAT number to verify (e.g., "PL1234567890", "DE 123456789", or "123456789") |
Example request
{
"vat": "PL8993033031"
}Response
| Field | Type | Description |
|---|---|---|
auditEvidence | object | |
↳ consultationNumber | string | |
↳ requestDate | string | |
companyDetails | object | |
↳ address | string | |
↳ city | string | |
↳ name | string | |
↳ postalCode | string | |
↳ street | string | |
isValid | boolean | |
status | string | |
tokensDeducted | integer | |
validationResult | object | |
↳ isFormatValid | boolean | |
↳ isViesRegistered | boolean | |
↳ reason | string | |
↳ viesStatus | string | |
vatDetails | object | |
↳ cleanVatNumber | string | |
↳ countryCode | string | |
↳ countryName | string | |
↳ isEuMember | boolean | |
↳ nationalNumber | string | |
↳ rawInput | string |
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.
400 | The body or a parameter failed validation. The details array names the field. |
401 | No key, a revoked key or a wrong header. Send x-api-key. |
402 | The wallet cannot cover this call. Top up or wait for the monthly grant. |
404 | The resource does not exist, or it is not yours. Both answer identically and cost nothing. |
429 | Over the per-minute quota of your tier. Back off and retry. |
5xx | Upstream 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 key | 10 |
| Free | 60 |
| Pro | 300 |
| Enterprise | 1200 |
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