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B2B Marketplace EU VAT Compliance

B2B marketplaces facilitating cross-border EU sales must verify buyer VAT numbers to determine the correct tax treatment for each transaction. The TaxID API provides real-time VIES validation so you can apply zero-rate correctly at scale.

Implementation steps

1. 1

   Validate at buyer onboarding

   When a business registers on your marketplace, collect their EU VAT number and call GET /api/v1/validate/:country/:vat from your server. Store the validation result (valid, company_name, company_address, validation timestamp) in the buyer's profile.

2. 2

   Apply correct tax treatment per transaction

   At transaction time, check the buyer's stored validation status. If the buyer has a validated 'active' VAT number in an EU country different from the seller's, apply zero-rate (reverse charge) treatment. Otherwise, apply the seller's local VAT rate.

3. 3

   Re-validate all buyers monthly

   Use the batch endpoint (POST /api/v1/validate) to re-validate up to 25 buyer VAT numbers per request. Run this job monthly for all buyers with reverse-charge status. Flag any returning 'invalid' for your compliance team to review and notify the buyer.

4. 4

   Include verified company details on invoices

   Populate invoices with the company_name and company_address from the TaxID validation response, not just from buyer self-registration. This satisfies EU invoice requirements and ensures the billing name matches the tax authority's records.

Code example

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');
}

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.

Evaluating EU VAT APIs? Compare TaxID vs Vatstack, Vatlayer, Avalara →

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