Wordpress - Remove JSON API links in header html

I see in filters.php "add_action( 'wp_head', 'rest_output_link_wp_head', 10, 0 )" Which makes me think this should do the trick to remove rel='https://api.w.org/'.

remove_action( 'wp_head',      'rest_output_link_wp_head'              );

The rest... * cough * seem to be in default-filters.php

remove_action( 'wp_head',      'wp_oembed_add_discovery_links'         );

To remove the rest_output_link_header

remove_action( 'template_redirect', 'rest_output_link_header', 11 );

Reference

• wp_oembed_add_discovery_links
• rest_output_link_wp_head
• rest_output_link_header

This custom function should help removing all links in the header and footer - you may put it inside the functions.php file of your active theme;

function remove_json_api () {

    // Remove the REST API lines from the HTML Header
    remove_action( 'wp_head', 'rest_output_link_wp_head', 10 );
    remove_action( 'wp_head', 'wp_oembed_add_discovery_links', 10 );

    // Remove the REST API endpoint.
    remove_action( 'rest_api_init', 'wp_oembed_register_route' );

    // Turn off oEmbed auto discovery.
    add_filter( 'embed_oembed_discover', '__return_false' );

    // Don't filter oEmbed results.
    remove_filter( 'oembed_dataparse', 'wp_filter_oembed_result', 10 );

    // Remove oEmbed discovery links.
    remove_action( 'wp_head', 'wp_oembed_add_discovery_links' );

    // Remove oEmbed-specific JavaScript from the front-end and back-end.
    remove_action( 'wp_head', 'wp_oembed_add_host_js' );

   // Remove all embeds rewrite rules.
   add_filter( 'rewrite_rules_array', 'disable_embeds_rewrites' );

}
add_action( 'after_setup_theme', 'remove_json_api' );

And this snippet completely disable the REST API and shows the content below when you visit http://example.com/wp-json/, were example.com is the domain name of your website;

{"code":"rest_disabled","message":"The REST API is disabled on this site."}

In order to disable WordPress REST API, use the snippet below;

function disable_json_api () {

  // 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' );

}
add_action( 'after_setup_theme', 'disable_json_api' );