Josh Mckibbin

The <a href="https://kibb.in/ssmtp" rel="nofollow ugc">Simple SMTP Mailer</a> plugin allows you to easily configure WordPress to use SMTP instead of the PHP mail function.
This should only really be used in a development environment.
<h3>Simple SMTP Mailer Settings</h3>
<ul>
<li>Host: The mail server (Defaults to smtp.gmail.com)</li>
<li>Username: The username used for connecting to the SMTP server</li>
<li>Password: The password used for connecting to the SMTP server</li>
<li>Port: The port to use when sending an email (587, 465 or 25. Defaults to 587)</li>
<li>Security: The type of encryption security to use when sending an email (TLS or SSL. Defaults to TLS)</li>
<li>Debug: Enable debugging</li>
</ul>
All settings can be overridden by assigning array values to the SSMTP_MAILER constant in wp-config.php. This is useful for automating local deployment.
<pre><code>define(
 'SSMTP_MAILER',
 array(
 'host' => emailhost.com,
 'username' => username,
 'password' => password,
 'port' => 25,
 'security' => 'SSL'
 )
);
</code></pre>

Simple SMTP Mailer

Simplifies local development by configuring WordPress to use SMTP instead of the PHP mail() function

FolioVision

This plugin reconfigures the wp_mail() function to use SMTP instead of mail() and creates an options page that allows you to specify various options.
You can set the following options:
<ul>
<li>Specify the from name and email address for outgoing email.</li>
<li>Choose to send mail by SMTP or PHP’s mail() function.</li>
<li>Specify an SMTP host (defaults to localhost).</li>
<li>Specify an SMTP port (defaults to 25).</li>
<li>Choose SSL / TLS encryption (not the same as STARTTLS).</li>
<li>Choose to use SMTP authentication or not (defaults to not).</li>
<li>Specify an SMTP username and password.</li>
</ul>
Also adds subject to headers for SendGrid Activity Screen. SengGrid is a powerful SMTP service, however it’s Activity Log screen misses the message subjects. Our plugin adds that back in!

WP Mail SMTP SendGrid Edition

Based on WP Mail SMTP. Also adds subject for display on SendGrid Activity Screen.

Simple SMTP Mailer vs WP Mail SMTP SendGrid Edition