EU VAT validation in Node.js
Implement EU VAT number validation in a Node.js or Express application. Includes error handling, caching strategy, and TypeScript types for the API response.
Implementation steps
- 1
Install node-fetch or use native fetch
- 2
Create validateVAT helper function
- 3
Add error handling for VIES unavailability
- 4
Cache results in Redis or memory
Code example
Node.js
const res = await fetch(
'http://localhost:3000/api/v1/validate/DE/DE123456789',
{ headers: { 'Authorization': 'Bearer YOUR_API_KEY' } }
);
const { valid, status, company_name, company_address } = await res.json();
if (valid) {
console.log(`Valid EU business: ${company_name}`);
} else if (status === 'service_unavailable') {
// VIES is temporarily down — retry or allow with manual check
console.log('VIES unavailable — check back in a few minutes');
} else {
console.log('Invalid VAT number — charge local tax rate');
}Python
import requests
res = requests.get(
"http://localhost:3000/api/v1/validate/DE/DE123456789",
headers={"Authorization": "Bearer YOUR_API_KEY"}
)
data = res.json()
if data["valid"]:
print(f"Valid: {data['company_name']}")
elif data["status"] == "service_unavailable":
print("VIES temporarily unavailable")
else:
print("Invalid VAT number")API response
The TaxID API returns a consistent JSON response for every validation request:
{
"valid": true,
"status": "active",
"country_code": "DE",
"vat_number": "123456789",
"company_name": "Example GmbH",
"company_address": "Musterstraße 1, 10115 Berlin",
"request_date": "2026-05-10T00:00:00.000Z",
"cached": false,
"request_id": "req_01j..."
}Error handling
The API uses a consistent Stripe-style error format. Always handle service_unavailable separately — VIES has occasional downtime and you should not reject valid customers during outages.
activeVAT number is valid and the business is registered
invalidVAT number format is wrong or not registered in VIES
service_unavailableVIES or the national system is temporarily down — retry later
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