Martin Lormes

If a comment is held for moderation an email message is sent to the comment author with a link to verify the comment author’s email address. When the comment author clicks on that link the comment gets approved immediately. This makes discussions more lively as users don’t have to wait for the blog admin to approve the comment.
Blog owners may also choose to hold the comments in the moderation queue even after successful verification. The verification status is shown in the comment lists in the admin.
If an author has a previously approved comment and his comments gets approved automatically according to the ‘comment_whitelist’ option in WordPress no email is sent.
If a comment is classified as spam by Akismet or another anti-spam plugin no email is sent.
This plugin uses the <code>commentmeta</code> table and thus requires WordPress 2.9
PHP5 strongly recommended

Comment E-Mail Verification

Wish it supported embedded html in the verification email. One note. You must have Settings -> Discussion -> Comment must be manually approved checked in order for it to work. Once I figured that out, it works just fine.

Still works

If a comment is held for moderation an email message is sent to the comment author with a link to verify the comment author's email address.

emailable

Verify emails in real-time with Emailable.
Integrate with Emailable’s email verification API through this official plugin. Reduce spam and increase the quality of your signups by verifying emails directly from any form.
This is compatible with all major WordPress Forms and plugins that use the is_email function to validate email addresses. 
This includes, but is not limited to:
<ul>
<li>WordPress’s default registration and comment forms</li>
<li>WooCommerce’s registration and checkout form</li>
<li>Gravity Forms</li>
<li>Contact Form 7</li>
<li>Ninja Forms</li>
<li>Jetpack Forms</li>
</ul>
Emailable’s verification includes:
<ul>
<li>Disposable Email Detection</li>
<li>Accept-All Email Detection</li>
<li>MX Record Detection</li>
<li>SMTP Provider Details</li>
<li>Misspelled Domain Detection</li>
<li>Syntax Validation</li>
<li>Domain Validation</li>
<li>SMTP Verification</li>
<li>Email Deduplication</li>
<li>Role Email Detection</li>
<li>Free Email Detection</li>
<li>Email Quality Score</li>
<li>Anti-Greylisting Technology</li>
</ul>
To use this plugin, <a href="https://app.emailable.com/signup/" rel="nofollow ugc">sign up for a free Emailable account</a>, create an API key. All new signups will receive 250 free credits. 
What makes Emailable special?
<ul>
<li>Best in class performance: 30k emails verified per minute</li>
<li>Most Advanced Email Detection: Free, No Reply, Role, Accept-All, Disposable, and Mailbox Full</li>
<li><a href="https://emailable.com/guarantee/" rel="nofollow ugc">99%+ Deliverability Guarantee</a></li>
<li>99.99% Uptime</li>
<li>24/7 Support</li>
<li>SOC 2 Type II certified</li>
<li>GDPR, Privacy Shield, CCPA, and LGPD compliant</li>
</ul>
See more information about data privacy in the links below:
<ul>
<li><a href="https://emailable.com/terms-of-service/" rel="nofollow ugc">Emailable’s Terms of Service</a></li>
<li><a href="https://emailable.com/privacy-policy/" rel="nofollow ugc">Emailable’s Privacy Policy</a></li>
<li><a href="https://emailable.com/data-processing-agreement/" rel="nofollow ugc">Emailable’s Data Protection Agreement</a></li>
<li><a href="https://emailable.com/anti-spam-policy/" rel="nofollow ugc">Emailable’s Anti-Spam Policy</a></li>
</ul>

Emailable – Premium Email Verification & Validation

Verify emails in real-time with Emailable.

Comment E-Mail Verification vs Emailable – Premium Email Verification & Validation