WordPress Snippets

function.php

<?php

/**
*    Disables WordPress Rest API for external requests
*/
function restrict_rest_api_to_localhost() {
    $whitelist = array('127.0.0.1', "::1");

    if(!in_array($_SERVER['REMOTE_ADDR'], $whitelist)){
        die('REST API is disabled.');
    }
}
add_action( 'rest_api_init', 'restrict_rest_api_to_localhost', 1 );