Postnummervalidering i kassan för finländska leveranszoner

# Server-side: check whether a postcode can be delivered to
curl -X POST https://api.deliveryzone.fi/api/v1/delivery/check \
  -H "X-Api-Key: dz_live_..." \
  -H "Content-Type: application/json" \
  -d '{"destinationPostcode":"00100","basketValueCents":4500}'

# Response: in zone
{
  "canDeliver": true,
  "matchedZoneName": "Helsinki Center",
  "priceCents": 590,
  "currency": "EUR",
  "estimatedDeliveryMinutes": 45,
  "reasonCode": "DELIVERABLE"
}

// Server-side only — never expose your API key in browser code
async function checkDelivery(postcode, basketValueCents) {
  const res = await fetch("https://api.deliveryzone.fi/api/v1/delivery/check", {
    method: "POST",
    headers: {
      "X-Api-Key": process.env.DZ_KEY,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ destinationPostcode: postcode, basketValueCents }),
  });
  return res.json();
}

// PHP — server-side, keep API key out of frontend
$response = wp_remote_post('https://api.deliveryzone.fi/api/v1/delivery/check', [
  'headers' => [
    'X-Api-Key'      => get_option('dz_api_key'),
    'Content-Type' => 'application/json',
  ],
  'body' => wp_json_encode([
    'destinationPostcode' => $postcode,
    'basketValueCents'    => $basket_cents,
  ]),
]);
$data = json_decode(wp_remote_retrieve_body($response), true);