This plugin when activated automatically redirects all email sent through wp_mail/phpmailer to the user currently logged in or the site administrator.
The redirected email contains information about where the original email would have been sent to.
Use this plugin if you want to test email-sending features without actually sending emails our to anyone but yourself. I wrote this plugin to ease debugging with subscribe2.
Since Version 1.2 you can choose whether to redirect all email to the currently logged in user (default), the site administrator (only wpmu) or the blog administrator.

Mail Debug

Redirects all email sent through wordpress to the user currently logged in or the site administrator.

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

Mail Debug vs Simple SMTP Mailer