WP REST API Disable

admin.php

<?php
    /**
     * $. Remove & disable JSON API
     ******************************************************************************/

    function wpst_remove_json_api() {
    
        /**
         * Remove API scripts from header/footer
         */
        remove_action( 'wp_head', 'rest_output_link_wp_head', 10 );
        remove_action( 'wp_head', 'wp_oembed_add_discovery_links', 10 );
        remove_action( 'wp_head', 'wp_oembed_add_discovery_links' );
        remove_action( 'wp_head', 'wp_oembed_add_host_js' );
        remove_action( 'rest_api_init', 'wp_oembed_register_route' );
        remove_filter( 'oembed_dataparse', 'wp_filter_oembed_result', 10 );
        add_filter( 'embed_oembed_discover', '__return_false' );
        
        /**
         * Disable API from working if possible
         */
        add_filter( 'json_enabled', '__return_false' );
        add_filter( 'json_jsonp_enabled', '__return_false' );
        add_filter( 'rest_jsonp_enabled', '__return_false' );
        
        /**
         * Remove oembed and REST pingbacks
         */
        remove_action( 'wp_head', 'rest_output_link_wp_head', 10 );
        remove_action( 'wp_head', 'wp_oembed_add_discovery_links', 10 );
        remove_action( 'template_redirect', 'rest_output_link_header', 11 );
    }

    add_action( 'init', 'wpst_remove_json_api' );
    
    
    
    /**
     * Force a 403 Forbidden error
     */
    function wpst_disable_json_api_access( $result ) {
    
        if ( ! empty( $result ) ) {
            return $result;
        }
        
        if ( ! is_user_logged_in() ) {
            return new WP_Error( 'rest_not_logged_in', 'You are not currently logged in.', ['status' => 401] );
        }
    }
    
    add_action( 'rest_authentication_errors', 'wpst_disable_json_api_access' );