Crypto checkout
on WordPress

{
  "order_id": "1042",
  "status": "paid",
  "price_amount": 49.99,
  "price_currency": "USD",
  "callback_token": "a7f3c1e9d2b84f60a1c5e8d7b3f92a04",

  "event": "order.paid",
  "event_id": "evt_01J8W2Q5N3XK",
  "api_version": "2024-07-27"
}

<?php
// WooCommerce auth is NOT the HMAC scheme custom stores use.
//
// On checkout the plugin stores the per-order token we return:
//     $order->add_meta_data(self::ORDER_TOKEN_META_KEY, $gateway_order->token, true);
//
// On callback it compares that stored token against the one in the body:
private function is_token_valid(WC_Order $order, string $token) {
    $order_token = $order->get_meta(static::ORDER_TOKEN_META_KEY);
    // hash_equals, not ==, so a wrong token can't be recovered by timing.
    return !empty($order_token) && hash_equals($order_token, $token);
}

// Then an amount guard, so a "paid" callback for less than the order total
// cannot complete the order:
private function is_order_paid_status_valid(WC_Order $order, $price) {
    return $order->get_total() >= (float) $price;
}

<?php
// The settings screen exposes the CPT-status to WC-status mapping, and the
// saved values are merged OVER the defaults, so you only override what differs.
//
// Send confirming orders to processing instead of on-hold:
add_action('init', function () {
    $settings = get_option('woocommerce_cptpayment_settings', []);
    $settings['order_statuses'] = array_merge(
        $settings['order_statuses'] ?? [],
        ['confirming' => 'wc-processing']
    );
    update_option('woocommerce_cptpayment_settings', $settings);
});

<?php
// The gateway drives ordinary WooCommerce status transitions, so you don't need
// plugin-specific hooks. Use the WC ones you already know.

add_action('woocommerce_order_status_completed', function ($order_id) {
    $order = wc_get_order($order_id);
    if ($order->get_payment_method() !== 'cptpayment') {
        return;
    }
    // Crypto payment settled. Grant access, ship, notify fulfilment.
    my_fulfil($order);
}, 10, 1);

// Underpaid lands on-hold by default. Catch it and flag for review.
add_action('woocommerce_order_status_on-hold', function ($order_id) {
    $order = wc_get_order($order_id);
    if ($order->get_payment_method() !== 'cptpayment') {
        return;
    }
    $order->add_order_note('Crypto payment needs review: underpaid or confirming.');
}, 10, 1);

<?php
// The gateway has a built-in percentage fee or discount for paying in crypto
// (negative values discount). Set it from the settings screen, or in code:
add_action('init', function () {
    $settings = get_option('woocommerce_cptpayment_settings', []);
    $settings['mark_up'] = -2;   // 2% off for paying in crypto
    update_option('woocommerce_cptpayment_settings', $settings);
});