// First, instantiate the SDK with your API credentials
$mg = Mailgun::create('key-example'); // For US servers
$mg = Mailgun::create('key-example', 'https://api.eu.mailgun.net'); // For EU servers

// Now, compose and send your message.
// $mg->messages()->send($domain, $params);
$mg->messages()->send('example.com', [
  'from'    => 'bob@example.com',
  'to'      => 'sally@example.com',
  'subject' => 'The PHP SDK is awesome!',
  'text'    => 'It is so simple to send a message.'
]);