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

ahasend

Most hosting providers aren\’t equipped to handle high-volume email sending or guarantee fast, reliable delivery, leading to delayed emails and poor inbox placement. 
The AhaSend WordPress plugin seamlessly connects your WordPress site with AhaSend’s <a href="https://ahasend.com" rel="nofollow ugc">reliable email delivery platform</a> via an HTTP API, improving email sending performance compared to sending with SMTP and bypassing issues such as blocked SMTP ports by hosting providers. Optimize your transactional emails with easy integration and advanced features designed for speed and enhanced inbox placement. With AhaSend, you benefit from real-time tracking, customizable data retention, and secure email handling to ensure efficient and accurate delivery. Perfect for e-commerce, membership sites, and more, AhaSend’s plugin provides robust, fast email solutions without the hassle.
<h3>External services</h3>
This plugin sends email content to the AhaSend API everytime WordPress needs to send an email, and AhaSend – as an Email Service Provider – delivers the email to the recipients. 
Please review AhaSends <a href="https://ahasend.com/terms" rel="nofollow ugc">Terms of Use</a> and <a href="https://ahasend.com/privacy" rel="nofollow ugc">Privacy Policy</a> before using this plugin.

AhaSend Email API

Connect your WordPress site to AhaSend for reliable, fast transactional email delivery with easy SMTP integration and real-time tracking.

Simple SMTP Mailer vs AhaSend Email API