Miquel Colomer

This plugin uses the uProc for WordPress API <a href="https://uproc.io" rel="nofollow ugc">https://uproc.io</a> to check if an email address really exists or not.
The plugin integrates with the is_email() function of WordPress. It works seamlessly with:
<ul>
<li>Contact Form 7</li>
<li>Jetpack/Grunion</li>
<li>WordPress registration forms</li>
<li>and with any other form which uses the is_email() function (no changes required).</li>
</ul>
The plugin can also be integrated into 3rd party forms that do not use the is_email() function.
<h4>How does it work?</h4>
The uProc API real-time validation process includes all of the following tests:
<ul>
<li>Syntax verification (IETF/RFC standard conformance)</li>
<li>DNS validation, including MX record lookup</li>
<li>Disposable email address (DEA) detection</li>
<li>Misspelled domain detection to prevent Typosquatting</li>
<li>Freemail address detection</li>
<li>SMTP connection and availability checking</li>
<li>Temporary unavailability detection</li>
<li>Mailbox existence checking</li>
<li>Catch-All testing</li>
<li>Greylisting detection</li>
<li>Block free domain emails (like Gmail, Hotmail, Yahoo, …)</li>
<li>Avoid email validations on Woocommerce orders</li>
</ul>
The plugin requires an API Key (free, no credit card required): 
<a href="https://app.uproc.io/#/signup" rel="nofollow ugc">https://app.uproc.io/#/signup</a>
We do not send any email to the recipient address during the entire validation process. All processing is done on our servers, your IP addresses and domains are not affected in any way by the Email-Validator service – absolutely no blacklisting risk for your IPs and domains.
Data Protection and Privacy Policy: see the Frequently Asked Questions section.
<h3>What is uProc</h3>
uProc is a SaaS platform where you can check or enrich any available field in your database. Please, check our catalog at 
<a href="https://app.uproc.io/#/tools" rel="nofollow ugc">https://app.uproc.io/#/tools</a> 
to find the right tool for you.
Next fields can be processed with our catalog: 
* Audio: speeches 
* Communication: Email, Mobile, Phone 
* Company: Cif, Name, Employee 
* Finance: Credit card, Account, Currency 
* Geographical: Country, City, Coordinates 
* Image: Screenshot, EXIF 
* Internet: Domain, IP, URI 
* Personal: Name, Surname, Gender 
* Product: EAN, UPC, ASIN, GTIN, ISBN 
* Security: Password, MD5, Luhn 
* Text: Uppercase, Lowercase, Lists

uProc for WordPress

I hope this plugin will be useful for your site.

You can validate emails on registration or comments.
Some cash is added to your account by default to test it.

The weak point: No other validation is supported yet when lots are available in the service catalog.

This will be solved soon. Mobile and landline phones validations are needed in my WordPress site.

Nice plugin, useful for my site

With the uProc for Wordpress plugin you can easily verify if an email address really exists and is valid. Additionally, you can check all existing too …

doublesharp

<h4>Validated Field Add-On</h4>
The Validated Field add-on for <a href="https://wordpress.org/extend/plugins/advanced-custom-fields/" rel="ugc">Advanced Custom Fields</a> 
provides a wrapper for other input types which allows you to provide client side input masking using the jQuery 
<a href="http://digitalbush.com/projects/masked-input-plugin/" rel="nofollow ugc">Masked Input Plugin</a>, server side validation using either PHP regular expressions 
or PHP code, the option of ensuring a field’s uniqueness for all posts by <code>post_type</code> and <code>meta_key</code>, <code>post_type</code>, or site wide, or a 
single post by meta_key, as well as marking a field as read-only. Edit your fields in the ACF Field Group editor and update code using the ACE.js 
IDE with autocomplete and syntax validation.
<h4>Features</h4>
<ol>
<li>Input Masking – easily set masks on text inputs to ensure data is properly formatted.</li>
<li>Server-Side Validation – validate the inputs using server side PHP code or regular expressions.</li>
<li>Uniqueness – ensure that the value being updated is not already in use.</li>
<li>Repeater Fields – validated fields within a <a href="http://www.advancedcustomfields.com/add-ons/repeater-field/" rel="nofollow ugc">Repeater Field</a>.</li>
<li>Read Only – specify a field as read-only allowing it to be displayed but not updated.</li>
<li>WordPress Multi Language – compatible with multilingual sites using the WPML plugin.</li>
<li>Conditional Logic – show and hide validated fields based on the values of other “switch” fields.</li>
</ol>
<h4>Compatibility</h4>
Requires <a href="https://wordpress.org/extend/plugins/advanced-custom-fields/" rel="ugc">Advanced Custom Fields</a> version 4.0 or greater.

Advanced Custom Fields: Validated Field

Adding my one star to inform people that this plugin is no longer working

Doesn't work in ACF Pro 5.6.2

The Validated Field add-on for Advanced Custom Fields provides input masking and server-side validation of other field types.

uProc for WordPress vs Advanced Custom Fields: Validated Field