Swift SMTP Mailer WPMU Plugin initial release

This plugin uses Swift Mailer library instead of PHPMailer. Why?

Check out the comparison here: https://www.swiftmailer.org/phpmailer/

The unique feature of SwiftMailer is that it also supports TLS, which is used by Gmail. If you are using Google Apps for Domain Email Hosting, this is a must-have.

This WPMU plugin is based on Swift SMTP Plugin made by ShiftThis. This initial release just removed the plugin option pages and made it compatible with WPMU. An improved version with option page is under development.

Download from WPMUdev.org


  1. Unzip the package;
  2. Modify the options in shiftthis-smtp.php file (see below for details);
  3. Upload all files to /wp-content/mu-plugins/.

SMTP Options

In shiftthis-smtp.php, modify the section below to your SMTP server settings:

  • $st_smtp_config[’server’]
    set to your email SMTP server setting (smtp.yourhost.com).
  • $st_smtp_config[’username’]
    set to the username used to login to your SMTP account.
  • $st_smtp_config[’password’]
    set to the password used to login to your SMTP account.
  • $st_smtp_config[’ssl’]
    If your server requires TLS or SSL, set to ‘tls’ or ’ssl’, otherwise set to ‘No’.
  • $st_smtp_config[’port’]
    Set to 25 for a default port setting, if you use TLS or SSL then enter 465, otherwise enter your custom port number.

Example configurations:

  1. Normal port 25 SMTP
  2. Gmail SMTP servers: