EU VAT validation on Vercel Edge

// app/api/validate-vat/route.ts
// Runs at the Vercel edge — global, sub-50ms cold starts

import { NextRequest, NextResponse } from 'next/server';

export const runtime = 'edge';

export async function GET(request: NextRequest) {
  const { searchParams } = new URL(request.url);
  const country = searchParams.get('country');
  const vat     = searchParams.get('vat');

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

  const res = await fetch(
    `http://localhost:3000/api/v1/validate/${country}/${vat}`,
    {
      headers: { 'Authorization': `Bearer ${process.env.TAXID_API_KEY}` },
      next: { revalidate: 3600 },  // cache validated results for 1 hour
    }
  );

  const result = await res.json();
  return NextResponse.json(result);
}

# Test locally:
# curl "http://localhost:3000/api/validate-vat?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
# }