Create a new custom Webhook in WooCommerce with a custom response

class-webhook.php

<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( ! class_exists( 'WC_Sample_Webhook', false ) ) :

	class WC_Sample_Webhook {

		//Init notices
		public static function init() {

			//Create topics and pair them with action to call them
			add_filter( 'woocommerce_webhook_topic_hooks', array( __CLASS__, 'add_topics'), 10, 2 );

			//Add topics to the admin dropdown menu when you create the webhook
			add_filter( 'woocommerce_webhook_topics' , array( __CLASS__, 'add_topics_admin_menu'), 10, 1 );

			//Register the name of your resource as a valid webhook resource
			add_filter( 'woocommerce_valid_webhook_resources', array( __CLASS__, 'add_resource'), 10, 1 );

			//Register custom event names as valid events
			add_filter( 'woocommerce_valid_webhook_events', array( __CLASS__, 'add_event'), 10, 1 );

			//Create custom response
			add_filter( 'woocommerce_webhook_payload', array( __CLASS__, 'create_payload'), 10, 4 );
		}

		public static function add_topics($topic_hooks, $webhook) {
			if ( 'your_resource' == $webhook->get_resource() ) {
				$topic_hooks = array(
					'your_resource.created' => array('your_resource_action_created'), //The your_resource.created webhook topic will run when you call do_action('your_resource_action_created') in your plugin
					'your_resource.updated' => array('your_resource_action_updated'),
					'your_resource.custom_event' => array('your_resource_action_custom_event'),
				);
			}
			return $topic_hooks;
		}

		public static function add_topics_admin_menu( $topics ) {
			$front_end_topics = array(
				'your_resource.created'  => 'Your Resource - created',
				'your_resource.updated'  => 'Your Resource - updated',
				'your_resource.custom_event'  => 'Your Resource - custom event',
			);
			return array_merge( $topics, $front_end_topics );
		}

		//You need to register your resource name, because only coupon', 'customer', 'order', 'product' are valid by default
		public static function add_resource( $resources ) {
			$resources[] = 'your_resource';
			return $resources;
		}

		//You need to register any custom event names, because only 'created', 'updated', 'deleted', 'restored' are valid by default
		public static function add_event( $events ) {
			$events[] = 'custom_event';
			return $events;
		}

		public static function create_payload( $payload, $resource, $resource_id, $id ) {
			if ( 'your_resource' == $resource && empty( $payload ) ) {
				$webhook      = new WC_Webhook( $id );
				$event        = $webhook->get_event();
				$payload 			= array('test' => 123);
			}
			return $payload;
		}

  }

	WC_Sample_Webhook::init();

endif;