Max Cutler

This plugin brings XML-RPC API enhancements from the WordPress 3.4 release to previous versions 
of WordPress (3.3 and earlier). It also adds new user management methods.
It is derived from Prasath Nadarajah’s GSoC ’11 project to expand WordPress’ web services, 
although the exposed API methods are not compatible (different parameter names/types/orders).
<h4>Methods</h4>
New Methods:
<ul>
<li>wp.newUser – create a new user</li>
<li>wp.editUser – edit user information</li>
<li>wp.deleteUser – delete a specfic user</li>
</ul>
3.5 Methods for pre-3.5 sites:
<ul>
<li>wp.getUser – get information about a specific user</li>
<li>wp.getUsers – retrieve a list of users</li>
<li>wp.getProfile – retrieve information about the requesting user</li>
<li>wp.editProfile – edit the profile of the requesting user</li>
<li>wp.getRevisions – retrieve revisions for a specific post</li>
<li>wp.restoreRevision – restore a post revision</li>
</ul>
3.4 Methods for pre-3.4 sites:
<ul>
<li>wp.newPost – create a new post (of any post type)</li>
<li>wp.editPost – edit a post (of any post type)</li>
<li>wp.deletePost – delete a post (of any post type)</li>
<li>wp.getPost – get a specific post (of any post type)</li>
<li>wp.getPosts – get a list of posts</li>
<li>wp.getPostType – get information about a specific post type</li>
<li>wp.getPostTypes – get a list of registered post types</li>
<li>wp.getTaxonomy – get information about a specific taxonomy</li>
<li>wp.getTaxonomies – get a list of registered taxonomies</li>
<li>wp.newTerm – create a new term in a taxonomy</li>
<li>wp.editTerm – edit a term in a taxonomy</li>
<li>wp.deleteTerm – delete a term in a taxonomy</li>
<li>wp.getTerm – get information about a specific term in a taxonomy</li>
<li>wp.getTerms – get a list of term associated with a taxonomy</li>
</ul>

XML-RPC Modernization

excelent

This plugin updates the WordPress XML-RPC API to leverage the latest features of WordPress and move beyond the historical Blogger/metaWeblog/MT APIs.

Walter Ebert

This plugin does more than just using the <code>xmlrpc_enabled</code> hook, because that is only used “To disable XML-RPC methods that require authentication”.
Activating this plugin will also disable pingbacks, trackbacks, and Really Simple Discovery (RSD), because these rely on XML-RPC.
It works with any webserver, because it does not use the .htaccess file.
<h4>Testing the plugin</h4>
From the command line you can test if the plugin is working correctly using <a href="https://curl.haxx.se/" rel="nofollow ugc">cURL</a>. Replace the <code>example.com</code> link to match your website:
<pre><code>curl -d '<?xml version="1.0"?><methodCall><methodName>system.listMethods</methodName><params><param><value><string/></value></param></params></methodCall>' https://example.com/xmlrpc.php
</code></pre>
This should only return the following methods: 
– <code>system.multicall</code> 
– <code>system.listMethods</code> 
– <code>system.getCapabilities</code>

Remove XML-RPC Methods

Remove all WordPress methods from the XML-RPC API to increase security.

XML-RPC Modernization vs Remove XML-RPC Methods