PHP

composer require xurel/xurel-php

<?php
require 'vendor/autoload.php';

$xurel = new Xurel\Client(getenv('XUREL_API_KEY'));

$email = $xurel->emails->send([
  'from' => 'hello@yourdomain.com',
  'to' => ['user@example.com'],
  'subject' => 'Hello',
  'html' => '<p>Sent from PHP</p>',
  'type' => 'transactional',
]);

echo $email['id'];