I built a simple to use class in PHP for the namecheap.com API. It supports all of Namecheap’s API methods. I released the code on GitHub. Example of usage:

<?php
require 'namecheap.class.php';
$username = 'YOUR USERNAME';
$apiKey = 'YOUR API KEY';
$clientIp = 'IP WHERE THIS YOUR SCRIPT IS HOSTED';
$namecheap = new Namecheap ($username, $apiKey, $clientIp) ;
$data\["Command"\] = "namecheap.ssl.getList";
$returned = $namecheap->request($data);
print\_r($returned)
 ?>

GitHub release: https://github.com/nake89/namecheap