SMTP.com

<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.
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.
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.
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.


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.

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.

SMTP.com vs AhaSend Email API