\d+)', array( 'methods' => 'GET', 'callback' => 'my_awesome_func', )); }); add_action('rest_api_init', function () { register_rest_route('homegrade/v1', '/salut', array( 'methods' => 'GET', 'callback' => 'my_awesome_func', )); }); function my_awesome_func($request) { $id = $request['id']; $response = new WP_REST_Response("salut" . $id); $response->set_status(200); return $response; }