////////////////////////////////// //Custom route Rest API add_action( 'rest_api_init', function () { register_rest_route( 'myplugin/v1', '/author/(?P<id>\d+)', array( 'methods' => 'GET', 'callback' => 'my_awesome_func', 'permission_callback' => '__return_true' ) ); } ); function my_awesome_func( $data ) { $posts = get_posts( array( 'author' => $data['id'], ) ); if ( empty( $posts ) ) { return null; } return $posts[0]->post_title; } //Custom route Rest API //////////////////////////////////