require 'vendor/autoload.php';
use MailgunMailgun;

$mgClient = new Mailgun("key-383471b46ed52cc69baa3eea9ba1bf2d");
$domain = "sandboxfa3e9009746840be831c6edc9e9f1ee9.mailgun.org";
$result = $mgClient->sendMessage("$domain",
array('from' => 'Mailgun Sandbox - Test
       <postmaster@sandboxfa3e9009746840be831c6edc9e9f1ee9.mailgun.org>',
    'to' => 'email_1@gmail.com, email_2@gmail.com',
    'subject' => 'Mailgun bulk-msg test for KB',
    'text' => 'Your mail do not support HTML',
    'html' => 'html-portion here...',
    'recipient-variables' => '{"email_1@gmail.com": {"first":"Name-1",
     "id":1}, "email_2@gmail.com": {"first":"Name-2", "id": 2}}')
 );
 var_dump($result);
 ?>
 #===============================================