PHP integration

The Delivery Zone API accepts a JSON POST and returns a JSON response. Call it using file_get_contents with a stream context, cURL, or wp_remote_post in WordPress.

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When to call the API

Call the API inside your PHP request handling code — in a controller, a WordPress filter, or an API endpoint. Always server-side.

Important: keep API keys server-side: Never expose the API key in JavaScript output, HTML source, or any client-visible file. Store it in a config file outside the web root, an environment variable, or WordPress options.

Code example

// 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);

Error handling

When canDeliver is false (or null), the response includes a reasonCode field. Display this to the customer:

NOT_DELIVERABLE — postcode is outside your delivery zones, or not recognised (the API intentionally uses one generic code for both, to protect zone boundaries)
MINIMUM_ORDER_NOT_MET — basket value is below the zone's minimum order
BASKET_VALUE_REQUIRED — a basket value is needed to evaluate this destination's minimum-order or free-delivery rule

Always handle HTTP errors (5xx, timeout) gracefully. If the API is unreachable, fail safe — either reject the order or allow manual review.

Implementation checklist

Store API key in an environment variable or WordPress option
Validate postcode is 5 digits before calling the API
Handle cURL/wp_remote_post errors and non-200 responses
Test against a non-production delivery zone first
Confirm WooCommerce rejection behaviour if using WooCommerce

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