Jesin A

<p>Most email validators look for an <code>@</code> and a <code>.</code>(dot) some go further and blacklist certain domain names. But Mailgun’s Advanced email validation service goes deeper and looks for the existence of the domain name, presence of a <a href="http://en.wikipedia.org/wiki/MX_record" rel="nofollow ugc">MX record</a> and the custom ESP(Email Service Provider) grammar.<br />
The grammar here is the rules defined by each email provider. For example, Yahoo Mail addresses can only contain letters, numbers, underscores, and one period.<br />
So <code>user.name.abc@yahoo.com</code> perfectly passes the <a href="https://codex.wordpress.org/Function_Reference/is_email" rel="nofollow ugc">is_email()</a> function but can never exist as it contains more than one period. Such addresses can’t escape Mailgun’s Email validation.</p>
<h4>Why use Mailgun’s email validation service?</h4>
<ul>
<li>Performs the usual email syntax check.</li>
<li>Checks the existence of the email domain. So <code>user@some-random-characters.com</code> can’t escape.</li>
<li>Checks if the email domain has a MX record. So <code>anything@example.com</code> is caught.</li>
<li>Checks if the username complies with the grammar of its ESP (Email Service provider). Eg Gmail doesn’t allow usernames less than 6 characters and hyphens so <code>small@gmail.com</code> and <code>hyphen-user@gmail.com</code> can’t get away.</li>
</ul>
<h4>Why use this plugin?</h4>
<ul>
<li>Integrates with the <a href="https://codex.wordpress.org/Function_Reference/is_email" rel="nofollow ugc">is_email()</a> function of WordPress. So it works seamlessly with Contact Form 7, Jetpack/Grunion contact forms, WordPress registration form and any form which uses the <code>is_email()</code> function.</li>
<li>Kicks spam before it is inserted into the database</li>
<li>Ensures that the commenting process is uninterrupted even if Mailgun suffers a <a href="http://status.mailgun.com" rel="nofollow ugc">downtime</a></li>
<li>Works completely transparent, nothing changes in the frontend</li>
</ul>
<p>This plugin requires a Mailgun Public API Key which can be obtained by <a href="https://mailgun.com/signup" rel="nofollow ugc">signing up at Mailgun</a>.</p>
<p>If you’re trying out this plugin on a local WAMP/LAMP/MAMP installation make sure your system is connected to the Internet for this plugin to contact Mailgun.</p>
<h4>Available Languages</h4>
<ul>
<li>English</li>
<li>Serbo-Croatian by <a href="http://www.webhostinghub.com/" rel="nofollow ugc">Borisa Djuraskovic</a></li>
<li>Spanish by <a href="http://www.webhostinghub.com/" rel="nofollow ugc">Andrew Kurtis</a></li>
</ul>
<h4>Further Reading</h4>
<p>Read about Mailgun’s email validation service.</p>
<ul>
<li><a href="http://blog.mailgun.com/post/free-email-validation-api-for-web-forms/" rel="nofollow ugc">http://blog.mailgun.com/post/free-email-validation-api-for-web-forms/</a></li>
<li><a href="http://blog.mailgun.com/post/weekly-product-update-improvements-to-email-validation-api/" rel="nofollow ugc">http://blog.mailgun.com/post/weekly-product-update-improvements-to-email-validation-api/</a></li>
<li><a href="http://mailgun.github.io/validator-demo/" rel="nofollow ugc">Mailgun Address Validator demo</a> and its <a href="https://github.com/mailgun/validator-demo/tree/gh-pages" rel="nofollow ugc">source code</a></li>
<li>The <a href="https://websistent.com/wordpress-plugins/mailgun-email-validator/" rel="nofollow ugc">Mailgun Email Validator Plugin</a> official homepage.</li>
</ul>


Mailgun Email Validator

Implementing this plugin is straight forward and simple.

Works perfectly

Kick spam with a highly advanced email validation in comment forms, user registration and contact forms using Mailgun's Email validation service.

zerobounce

<p>Need an email validation tool to block invalid and high-risk emails on your WordPress website?</p>
<p>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.</p>
<h3>Key Features</h3>
<ul>
<li><strong>Automated real-time email validation</strong> – Automatically prevent selected email types from creating accounts, leaving comments, or signing up</li>
<li><strong>Detect more than 30+ email address types</strong> – Including invalid, abuse, disposable, spam trap, toxic domains, catch-all, and more</li>
<li><strong>Choose what to accept</strong> – Create your own rules for email validation and disallow emails based on status</li>
<li><strong>Email verification for 9 form types</strong> – Easily select which forms you want to protect with email validation</li>
<li><strong>Fast manual email validation</strong> – Verify any email address in the tools section using our interactive form</li>
<li><strong>Email validation API logs</strong> – Keep track of monthly email verifications, including status, sub-status, IP, date, and credits used</li>
</ul>
<h3>Benefits</h3>
<ul>
<li><strong>Keep your email list clean & accurate</strong></li>
<li><strong>Reduce your email bounce rate</strong></li>
<li><strong>Boost your inbox placement</strong></li>
<li><strong>Protect your email sender reputation</strong></li>
<li><strong>Improve email deliverability</strong></li>
<li><strong>Eliminate fraudulent, untrustworthy shoppers</strong></li>
<li><strong>Block spammers and spoofers</strong></li>
<li><strong>Keep your comments section clean</strong></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>
<p>And more support is being added gradually.</p>


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.

Mailgun Email Validator vs ZeroBounce Email Verification & Validation