Ikbear

BillionVerify Email Validator checks email addresses in real time as your forms are submitted, stopping fake, mistyped, disposable and undeliverable emails before they reach your database. Cleaner signups mean fewer bounces, less spam and healthier email campaigns.
The plugin verifies each address against the BillionVerify API — performing syntax, MX and SMTP mailbox checks — and rejects the submission when the address matches a status you have chosen to block.
Key features
<ul>
<li>Real-time verification during form submission (no front-end changes required).</li>
<li>Detects valid, invalid, disposable, catch-all, role and risky addresses.</li>
<li>Choose exactly which statuses block a submission — invalid only by default.</li>
<li>Custom error message shown to visitors.</li>
<li>Built-in connection test and single-email test tool in the admin.</li>
<li>Result caching to save credits on repeated addresses.</li>
<li>Fail-open by default: if the API is unreachable or credits run out, forms keep working.</li>
</ul>
Supported forms
<ul>
<li>Default WordPress registration form (including multisite signup)</li>
<li>WordPress comment form</li>
<li>WordPress lost-password form</li>
<li>WooCommerce checkout and account registration</li>
<li>Contact Form 7</li>
<li>WPForms</li>
<li>Gravity Forms</li>
<li>Elementor Pro Forms</li>
<li>Fluent Forms</li>
</ul>
<h3>Third-Party Service Usage</h3>
This plugin sends email addresses to the BillionVerify API (https://billionverify.com/) for verification. Through API calls to BillionVerify servers it verifies email addresses and retrieves account credit information, using the following endpoints:
<ul>
<li>Verify an email address: https://api.billionverify.com/v1/verify/single</li>
<li>Retrieve credit balance: https://api.billionverify.com/v1/credits</li>
</ul>
By installing and activating this plugin, you consent to the transmission of submitted email addresses to these URLs for the purpose of verification. Use of the BillionVerify service is subject to BillionVerify’s Terms of Service (https://billionverify.com/terms) and Privacy Policy (https://billionverify.com/privacy).

BillionVerify Email Validator

Real-time email verification for your WordPress forms. Block invalid, disposable, catch-all and role addresses using the BillionVerify API.

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.

BillionVerify Email Validator vs ZeroBounce Email Verification & Validation