virtab

Email Checker’s Advanced email verification service completes a deep cleaning by performing an SMTP simulation test to check if the mailbox actually exists on the destination mail server for the best email validation accuracy.
Lets face it, people misspell their email address and are completely unaware of it, resulting in a delivery failure due to a bounce or maybe even a spam complaint. Furthermore, you also just lost a potential customer for your business! What is very interesting is most of these invalid email addresses are a result of a simple misspelled domain such as “hotmail.con”, “gnail.com”, or “yahoo.cmo”.
For example “jane@gmail.cmo” perfectly passes the <a href="https://codex.wordpress.org/Function_Reference/is_email" rel="nofollow ugc">is_email()</a> function, but does not really exist. Such addresses cannot escape Email Checker’s email verification test, ensuring you do not lose any valuable leads due to typos, as well as preventing spam signups by bots and more.
Email Checker can verify email addresses by detecting and revising typos, invalid syntax, invalid domain DNS, invalid MX DNS, disposable addresses, role accounts, free email providers, frequent complainers, offensive words, spam traps, honey pots, blacklists, catchalls, greylistings, mailbox exists, mailbox full and mailbox does not exist.
This email validation plugin integrates perfectly with other major plugins such as Contact Form 7, Gravity Forms, Ninja Forms and any other plugins that use the is_email() function. This plugin will validate email addresses in real-time and notify the user immediately so they can change it before submitting.
This plugin requires an Email Checker API Key and for credits to be purchased. You can create an account for Email Checker and purchase credits here: <a href="https://www.emailchecker.io" rel="nofollow ugc">Email Checker</a> (Signup in less than 30 seconds).
NOTE: You must have credits inside your <a href="https://www.emailchecker.io" rel="nofollow ugc">www.emailchecker.io</a> account in order for it to validate email addresses in your website’s forms.

Email Checker

Prevent spam signups by bots and lost customers in comment, registration, and contact forms using Email Checker's Email Verification Plugin.

dueclic

turboSMTP

Validates email addresses using the turboSMTP API in: 
– WooCommerce registration and checkout 
– Contact Form 7 
– WpForms 
– WordPress comments and registration 
– MC4WP 
– Gravity Forms 
– Elementor Forms
The turboSMTP Email Validator for WordPress plugin ensures that email addresses provided during user registration and checkout are valid. It uses the turboSMTP API to perform the validation, enhancing the quality of email addresses collected and reducing the number of invalid emails in your database.
<h3>Features</h3>
<ul>
<li>Validates email addresses in different forms (WooCommerce, CF7, WpForms, WordPress comments and registration, MC4WP, Gravity Forms, Elementor Forms)</li>
<li>Uses the turboSMTP API for email validation.</li>
<li>Stores validated email addresses in a custom database table.</li>
<li>Provides an admin settings page to configure API keys and enable/disable the service.</li>
<li>Displays a list of validated email addresses in the admin area.</li>
<li>Bypass validation for individual email addresses or entire domains using the whitelist functionality.</li>
</ul>
<h3>Usage</h3>
<ul>
<li>Enable turboSMTP Email Validator: Go to “Settings” > “turboSMTP Email Validator” and check the “Enable Email Validation” option.</li>
<li>Set API Keys: Enter your turboSMTP consumerKey and consumerSecret in the provided fields.</li>
<li>View Validated Emails: Check the list of validated emails in the “Validated Emails” section on the settings page.</li>
</ul>

turboSMTP Email Validator

Email validation tool in WordPress forms registrations using turboSMTP API

Email Checker vs turboSMTP Email Validator