b4ecommerce

A lightweight plugin that checks for the most common email typos in the customer’s email and provides them with a warning. Using this plugin your customers will be much more likely to enter a valid email address, which will simplify and improve your order management.
USAGE 
You don’t need to configure the plugin, just upload and activate it and it’s ready to go.
CURRENTLY CHECKING FOR THE FOLLOWING EMAIL DOMAINS
<ul>
<li>Gmail</li>
<li>Hotmail</li>
<li>Outlook</li>
<li>Protonmail</li>
<li>Yahoo</li>
</ul>

Checkout email validation for WooCommerce

A lightweight plugin that checks for the most common email typos in the customer's email and provides them with a warning.

zerobounce

Need an email validation tool to block invalid and high-risk emails on your WordPress website?
The ZeroBounce email verification plugin assists users by validating email addresses entered into your registration forms, comments sections, eCommerce shops, and more. Install the plugin, connect your API key, and select the forms you want to monitor with email validation.
<h3>Key Features</h3>
<ul>
<li>Automated real-time email validation – Automatically prevent selected email types from creating accounts, leaving comments, or signing up</li>
<li>Detect more than 30+ email address types – Including invalid, abuse, disposable, spam trap, toxic domains, catch-all, and more</li>
<li>Choose what to accept – Create your own rules for email validation and disallow emails based on status</li>
<li>Email verification for 9 form types – Easily select which forms you want to protect with email validation</li>
<li>Fast manual email validation – Verify any email address in the tools section using our interactive form</li>
<li>Email validation API logs – Keep track of monthly email verifications, including status, sub-status, IP, date, and credits used</li>
</ul>
<h3>Benefits</h3>
<ul>
<li>Keep your email list clean & accurate</li>
<li>Reduce your email bounce rate</li>
<li>Boost your inbox placement</li>
<li>Protect your email sender reputation</li>
<li>Improve email deliverability</li>
<li>Eliminate fraudulent, untrustworthy shoppers</li>
<li>Block spammers and spoofers</li>
<li>Keep your comments section clean</li>
</ul>
<h3>Supported Forms/Plugins</h3>
<ul>
<li>Contact Form 7</li>
<li>WPForms</li>
<li>Ninja Forms</li>
<li>Formidable Forms</li>
<li>WooCommerce</li>
<li>WordPress Post Comments</li>
<li>WordPress Registration</li>
<li>MC4WP: Mailchimp for WordPress</li>
<li>Gravity Forms</li>
<li>Fluent Forms</li>
<li>WS Forms</li>
<li>Mailster Forms</li>
<li>Forminator Forms</li>
</ul>
And more support is being added gradually.

ZeroBounce Email Verification & Validation


I have tested this plugin on several of my personal and business websites, it's awesome. No more spam and fake signups. Service pricing is also decent. Recommended.


Excellent in blocking SPAM


You have a problem with NF form validation. It detects html fields that contains emails (eg mailto links) as email fields and validates those.



if (!empty($value) && is_string($value) && preg_match('/@.+\./', $value) && !str_contains($value, "\n") && !str_contains($value, '\n')) {// rest of the code}



Your approach needs to be changed to:



if (!empty($value) && is_string($value) && preg_match('/@.+\./', $value) && !preg_match('/mailto:/i', $value)) {  $ninjaForm = new Zerobounce_Email_Validator_Form_Public('ninjaforms', $form_data['id']);   // rest of the code}



This should be safer to validate only email addresses (or use a better regex).


Ninja Forms problem

ZeroBounce validates emails on your WordPress site in real-time, blocking invalid and risky emails to improve deliverability and reduce bounce rates.

Checkout email validation for WooCommerce vs ZeroBounce Email Verification & Validation