UserCheck

<p>UserCheck blocks disposable and throwaway email addresses from your sign-up forms. The result: less spam, fewer fake accounts, and a cleaner user base.</p>
<h4>Supported plugins</h4>
<p>If you’re using any of these, UserCheck protects them automatically — nothing to configure:</p>
<ul>
<li>WordPress core (registration, comments, multisite signup, profile email change)</li>
<li>WooCommerce (classic checkout, Cart/Checkout Block, account registration, Edit-account email change)</li>
<li>Profile Builder (free + Pro)</li>
<li>Contact Form 7</li>
<li>WPForms</li>
<li>Elementor Pro Forms</li>
<li>Gravity Forms</li>
<li>Fluent Forms</li>
<li>Ninja Forms</li>
<li>Formidable Forms</li>
<li>MailPoet</li>
</ul>
<h4>Fallback for unsupported plugins</h4>
<p>For plugins without a built-in integration, a fallback check catches sign-ups from any other form on your site. It only runs when someone submits a form, so it won’t slow down your dashboard or background tasks. You can turn it off under Settings <span aria-hidden="true" class="wp-exclude-emoji">→</span> UserCheck <span aria-hidden="true" class="wp-exclude-emoji">→</span> Coverage.</p>
<h4>Choose what to block</h4>
<p>Pick which kinds of email addresses get blocked: domains that can’t receive email, disposable addresses, public providers (Gmail, Yahoo, etc.), forwarding services that hide the real address, and known spammers. Domains on your UserCheck account blocklist are always blocked.</p>
<h4>Lightweight by design</h4>
<p>Emails are checked only when users submit a form (registration, comment, checkout) — never re-checked for existing users or orders. No background scans, no surprises.</p>
<h4>Resilient by design</h4>
<p>If our service is ever down or slow, your site keeps working: sign-ups go through and the error is logged for review. Each request times out after 2 seconds, so an unresponsive API can’t hold up your forms.</p>
<h4>Full email or domain only</h4>
<p>Send the full email (more accurate) or just the domain.</p>
<h4>Extensible</h4>
<p>Developers can plug UserCheck into any plugin’s validation hook by calling <code>UserCheck::instance()->evaluate_email( $email )</code> and acting on the returned <code>action</code>, <code>reason</code>, and <code>message</code>.</p>
<h4>Translation ready</h4>
<p>All text in the plugin can be translated into any language.</p>
<h4>Works out of the box</h4>
<p>No configuration required. A free API key unlocks higher request limits.</p>
<p>Powered by <a href="https://www.usercheck.com" rel="nofollow ugc">UserCheck</a>, which tracks new disposable email providers as they appear so your site’s protection stays current.</p>
<h3>Privacy Policy</h3>
<p>The plugin sends the email address (or just its domain, depending on your settings) to the UserCheck API for validation. The request User-Agent identifies the plugin version, WordPress version, site URL, and which integration triggered the check (e.g. <code>wp_registration</code>, <code>wc_checkout</code>, or <code>fallback_is_email/<plugin-slug></code> when the fallback fires for an unsupported plugin). No other end-user data is sent. For more information on how UserCheck handles data, please visit <a href="https://www.usercheck.com/privacy" rel="nofollow ugc">https://www.usercheck.com/privacy</a>.</p>


Block disposable and throwaway email addresses on your WordPress site.

fixbounce

<p><strong>FixBounce Email Verifier</strong> checks if every email address on your site actually exists — not just if it looks valid, but if the mailbox is real. Install, activate, and you’re protected immediately. No account needed.</p>
<h4>How It Works</h4>
<p>Every email submitted on your site (registration, comment, contact form, checkout) is verified through the FixBounce API:</p>
<ol>
<li><strong>Syntax check</strong> — Is the email properly formatted?</li>
<li><strong>Disposable domain check</strong> — Is it a throwaway address? (350+ domains blocked)</li>
<li><strong>MX record check</strong> — Does the domain have a mail server?</li>
<li><strong>SMTP mailbox verification</strong> — Does the actual mailbox exist?</li>
<li><strong>Catch-all detection</strong> — Does the domain accept any address?</li>
<li><strong>Deliverability score</strong> — Deliverable, Risky, or Undeliverable</li>
</ol>
<p>All 6 checks run on every verification. The only difference between plans is how many verifications per day.</p>
<h4>Plans</h4>
<ul>
<li><strong>Trial (no signup)</strong> — 5 verifications/day. All features. Install and go.</li>
<li><strong>Free account</strong> — 10 verifications/day. Create a free account at <a href="https://fixbounce.com" rel="nofollow ugc">fixbounce.com</a> and add your API key.</li>
<li><strong>Pro ($29/mo)</strong> — 500 verifications/day + bulk user verification.</li>
</ul>
<h4>What Gets Protected</h4>
<ul>
<li><strong>Registration</strong> — Blocks signups with fake or non-existent emails</li>
<li><strong>Comments</strong> — Stops comments from disposable or invalid addresses</li>
<li><strong>Contact forms</strong> — Real-time validation on Contact Form 7, WPForms, Gravity Forms, Elementor, Ninja Forms, and any HTML form</li>
<li><strong>WooCommerce</strong> — Verifies billing email before order is placed</li>
</ul>
<h4>When the daily limit is reached</h4>
<p>Verification pauses until the next day. Forms, registrations, and comments work normally — they just skip the email check. A notice appears in the admin dashboard with upgrade options.</p>
<h4>Privacy</h4>
<p>Only the email address is sent to the FixBounce API for verification. No other user data is transmitted. See our <a href="https://fixbounce.com/privacy" rel="nofollow ugc">privacy policy</a>.</p>


FixBounce Email Verifier

Block fake, disposable, and non-existent emails via SMTP verification. 5 free verifications/day, no signup needed.

UserCheck vs FixBounce Email Verifier