Asif Rahaman

Sparrow Email OTP Verification for Contact Form 7 provides a robust security layer for your website by verifying user email addresses before form submission. This effectively blocks bots, spammers, and malicious actors from flooding your inbox with fake data or invalid leads.
<h3>Why this plugin is different:</h3>
Most existing OTP plugins require you to pay for their proprietary API or use their specific SMTP service to send codes. This often leads to unexpected monthly costs and vendor lock-in.
This plugin is built with a “Your Server, Your Rules” philosophy. It sends OTP codes using the native <code>wp_mail()</code> function, meaning it utilizes your website’s default mail configuration or your preferred SMTP service. There are no extra costs, no hidden fees, and no third-party accounts required.
<h3>Features</h3>
<ul>
<li>Block Bots & Spam: Ensure every submission comes from a person with a valid, accessible email address.</li>
<li>Conditional Display (New v1.1.0): Dynamically hide verification elements inside an elegant wrapper box until an email string is typed.</li>
<li>Cost-Effective: Zero cost to send OTPs—it uses your existing server or SMTP setup.</li>
<li>Privacy First: No data is sent to external verification APIs; everything stays on your server.</li>
<li>Smart Detection: Automatically finds the email field in your Contact Form 7 forms.</li>
<li>Security-First Rate Limiting: Built-in protection to prevent OTP request abuse by limiting users to 3 attempts per 5 minutes per IP address.</li>
<li>Lightweight: Minimal footprint to ensure your site remains fast and passes Core Web Vitals.</li>
</ul>

Sparrow Email OTP Verification for Contact Form 7

Verify user emails with a secure OTP code to block bots and fake leads. Uses your own SMTP—no API fees, no subscriptions.

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.

Sparrow Email OTP Verification for Contact Form 7 vs ZeroBounce Email Verification & Validation