Totally Disable WP API Feature

				
					// Disable ALL API

remove_action('wp_head', 'rest_output_link_wp_head');
remove_action('wp_head', 'wp_oembed_add_discovery_links');
remove_action('template_redirect', 'rest_output_link_header', 11);
// Filters for WP-API version 1.x
add_filter('json_enabled', '__return_false');
add_filter('json_jsonp_enabled', '__return_false');

// Filters for WP-API version 2.x
// add_filter('rest_enabled', '__return_false');
add_filter('rest_jsonp_enabled', '__return_false');

// More REST API Hooks
remove_action('rest_api_init', 'wp_oembed_register_route'); // Remove the REST API endpoint.
remove_action('wp_head', 'wp_oembed_add_host_js'); // Remove oEmbed-specific JavaScript from the front-end and back-end.
add_filter('embed_oembed_discover', '__return_false'); // Turn off oEmbed auto discovery.
remove_filter('oembed_dataparse', 'wp_filter_oembed_result', 10); // Remove filter oEmbed results.
add_filter('rewrite_rules_array', 'adminify_disable_embeds_rewrites'); // Remove all embeds rewrite rules.

/**
* Remove all rewrite rules related to embeds.
* @param array $rules WordPress rewrite rules.
* @return array Rewrite rules without embeds rules.
*/
function adminify_disable_embeds_rewrites($rules)
{
    foreach ($rules as $rule => $rewrite) {
        if (false !== strpos($rewrite, 'embed=true')) {
            unset($rules[$rule]);
        }
    }

    return $rules;
}