SMTP.com

<p><a href="https://smtp.com" rel="nofollow ugc">SMTP.com</a> was the first company to provide email delivery at scale for customers unsatisfied with traditional sending methods. With over 22 years of email delivery success, SMTP.com is the trusted transactional and email relay provider for over 100,000 businesses worldwide. This WordPress integration for SMTP.com enables you to send and track your emails seamlessly.</p>
<p>Don’t worry about maintaining your email server or taking care of its IP reputation, forget about dealing with ISPs like Gmail, Yahoo or Microsoft in attempting to understand why your email isn’t reaching its destination. SMTP.com manages all this on your behalf. Simply create a SMTP.com account to <a href="https://registration.smtp.com/?afid=wpplugin" rel="nofollow ugc">get started</a> and set up this plugin. Although this plugin is free you will need a paid subscription with SMTP.com to send emails from your WordPress site.</p>
<p>You can send emails from your WordPress site using the SMTP.com API or the standard SMTP protocol. Our plugin will suggest the best way for you to send email even if your provider has restricted access to outbound internet ports. Either way, SMTP.com will still ensure your email gets delivered.</p>
<p>Another useful feature provided with our WordPress plugin is the ability to track your email delivery from within the plugin itself. See the results of your recent sends to ensure successful delivery or identify the reason why your particular email hasn’t been delivered.</p>



Didn't work with the API key, but managed with the login information.


Good

SMTP.com is a powerful and reliable SMTP delivery service that enables you to send and track high volume emails effortlessly.

MailerSend

<p>WordPress hosting companies are not optimized for high-volume email sending, which may result in some of your emails not getting delivered. MailerSend’s <a href="https://www.mailersend.com/features/smtp-relay" rel="nofollow ugc">dedicated SMTP server</a> will ensure that your forms, account notifications, e-commerce orders, and other transactional emails get delivered. By using this official SMTP plugin, you will:<br />
* Improve your email deliverability<br />
* Protect your domain reputation<br />
* Learn more about your recipients</p>
<h4>Deliverability</h4>
<p>Improve inbox performance and ensure a smooth customer experience by letting MailerSend take care of email sending. After a decade of email delivery experience, MailerSend’s deliverability experts understand what it takes to avoid spam filters, stay off blocklists and lower bounce rates.</p>
<h4>Domain reputation</h4>
<p>Keep your domain reputation safe with MailerSend’s email authentication practices. Give your customers the confidence that they’re interacting with an established brand, and let MailerSend manage the emails that could potentially damage your reputation.</p>
<h4>Analytics</h4>
<p>Understand what happens after an email gets sent. Access a wide range of key metrics—like open rates, bounce rates and click-through rates—to learn what works and what needs optimization so you can keep improving your email performance.</p>
<h4>Features</h4>
<ul>
<li>Avoid spam filters, prevent blocklisting, and lower hard bounce rates with powerful sending infrastructure</li>
<li>Automate the customer experience by connecting to thousands of other apps with Zapier</li>
<li>Get instant push updates with webhooks</li>
<li>Receive customer replies sent to your domain with an inbound route feature</li>
<li>Monitor all email interactions such as opens, clicks, open locations and devices. Plus, use your own subdomain and get a custom tracking link!</li>
</ul>
<h4>How it works</h4>
<ol>
<li>Install and activate the MailerSend plugin.</li>
<li>Add your <a href="https://app.mailersend.com/domains" rel="nofollow ugc">SMTP credentials</a> from MailerSend to establish the connection.</li>
<li>Test your connection to make sure it’s working.</li>
<li>And get sending!</li>
</ol>
<h4>Support</h4>
<p>Get help whenever you need it. <a href="https://www.mailersend.com/contact-us" rel="nofollow ugc">Contact us</a> or drop a message via live chat in the app. MailerSend’s dedicated support team works 24/7 because transactional emails never stop.</p>


MailerSend – Official SMTP Integration

<p>I'm using MailerSend as transactional email provider because they offer some great features that other providers don't have.<br />Beside this they have a great deliverability, sending speed and the MailerSend interface is really nice.</p>
<p>The plugin does a good job, but it's much to basic in my opinion.<br />I'm missing features like:<br />- Import / export settings<br />- Custom email headers<br />- a simple log file (now I need to check every issue via the MailerSend portal)</p>
<p>And why sending emails via SMTP and not via the MailerSend API?</p>

Basic features only, I need more to use the plugin for more projects

Improve your deliverability and avoid the spam box with MailerSend’s SMTP server. Check your analytics to improve your emails for better conversion!

SMTP.com vs MailerSend – Official SMTP Integration