Postmarkapp is a "email delivery in the cloud" service for sending out transactional emails in your applications. By using this service you don't need to worry about the setup and maintenance of a mailserver and as Postmarkapp is built to scale it can easily deal with large bursts of messages. Whilst an easy-to-use API is available this Zend_Mail transport allows you to easily switch out and use Postmark for mail delivery.

Usage is as simple as:

<?php
    Zend_Mail::setDefaultTransport( new Mail_Transport_Postmark( 'your_api_key' ) );
 
    $mail = new Zend_Mail();
    $mail->setFrom( 'alistair...', 'Alistair Phillips' );
    $mail->setReplyTo( 'some-other-address', 'Alistair Phillips' );
    $mail->addTo( 'new-user-address', 'Joe Smith' );
    $mail->setSubject( 'Welcome to...' );
    $mail->setBodyText( 'This is an example of a text body' );
    $mail->setBodyHtml( 'This is an example of an HTML body with <strong>bold</strong>' );
    $mail->send();
?>

One call to setDefaultTransport() and you're now using the cloud for delivery. Added support for attachments to the class.