EU VAT validation in Cloudflare Workers

// Store your API key as a Worker secret:
// $ wrangler secret put TAXID_API_KEY

export default {
  async fetch(request, env) {
    const { searchParams } = new URL(request.url);
    const country = searchParams.get('country');
    const vat     = searchParams.get('vat');

    if (!country || !vat) {
      return Response.json({ error: 'country and vat required' }, { status: 400 });
    }

    const res = await fetch(
      `http://localhost:3000/api/v1/validate/${country}/${vat}`,
      { headers: { 'Authorization': `Bearer ${env.TAXID_API_KEY}` } }
    );

    const result = await res.json();

    // Cache valid results at the Cloudflare edge for 1 hour
    const ttl = result.valid ? 3600 : 0;
    return Response.json(result, {
      headers: { 'Cache-Control': ttl ? `max-age=${ttl}` : 'no-store' }
    });
  }
};

# Test locally with wrangler:
# wrangler dev — then curl "http://localhost:8787?country=DE&vat=DE123456789"

# Or call the TaxID API directly:
curl "http://localhost:3000/api/v1/validate/DE/DE123456789" \
  -H "Authorization: Bearer $TAXID_API_KEY"

# {
#   "valid": true,
#   "status": "active",
#   "company_name": "Example GmbH",
#   "cached": false
# }