woocommerce-plugin-development

Create a PHP file with a plugin header declaring 'Requires Plugins: woocommerce', guard it with an ABSPATH check, and initialize your code on the woocommerce_loaded action. Then register hooks for the order, product, or checkout events you want to extend.

Register the tab with the woocommerce_settings_tabs_array filter, render fields via the woocommerce_settings_tabs_{id} action using woocommerce_admin_fields(), and save them with woocommerce_update_options() on the woocommerce_update_options_{id} action.

Yes, plugins reading order data with get_post_meta() fail when High-Performance Order Storage is enabled because orders move to custom tables. Use $order->get_meta() and $order->update_meta_data() with $order->save(), and declare compatibility via FeaturesUtil::declare_compatibility().

Extend the WC_Shipping_Method class, register it through the woocommerce_shipping_methods filter, and declare support for shipping-zones and instance-settings. Implement calculate_shipping() to call $this->add_rate() with an id, label, and computed cost.

A 403 occurs when the permission_callback rejects the request. For admin endpoints use current_user_can('manage_woocommerce') as the permission_callback, and register routes inside the rest_api_init action with register_rest_route().

Hooks like order status transitions can fire repeatedly, causing duplicate emails or double stock reduction. Guard against reprocessing with a static flag or transient, or check execution counts with did_action() before running your logic.