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Mailgun Email Validator

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

Most email validators look for an @ and a .(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 MX record and the custom ESP(Email Service Provider) grammar. 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. So perfectly passes the is_email() function but can never exist as it contains more than one period. Such addresses can't escape Mailgun's Email validation.

Why use Mailgun's email validation service?

Why use this plugin?

  • Integrates with the is_email() function of WordPress. So it works seamlessly with Contact Form 7, Jetpack/Grunion contact forms, WordPress registration form and any form which uses the is_email() function.
  • Kicks spam before it is inserted into the database
  • Ensures that the commenting process is uninterrupted even if Mailgun suffers a downtime
  • Works completely transparent, nothing changes in the frontend

This plugin requires a Mailgun Public API Key which can be obtained through a free sign-up at Mailgun(No credit card required).

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.

Available Languages

Further Reading

Read about Mailgun's email validation service.

Author Jesin
Contributors jesin
Tags anti-spam, comments, contact form, contact form 7, email validation, grunion, jetpack, spam, validation
  1. mailgun-email-validator screenshot 1

    Enter your public API key to begin validation.

  2. mailgun-email-validator screenshot 2

    A comment with an incorrect email address.

  3. mailgun-email-validator screenshot 3

    This plugin in action on the user registration page.

  4. mailgun-email-validator screenshot 4

    Email validation in a contact form.

  1. Unzip and upload the mailgun-email-validator folder to the /wp-content/plugins/ directory.
  2. Activate the Mailgun Email Validator plugin through the 'Plugins' menu in WordPress.
  3. Configure the plugin by going to General > Email Validation page.
  4. Signup for a Mailgun account (it is completely free no credit card required).
  5. Login, copy and paste your public API key to General > Email Validation page.


  • 16th October 2016
  • Removed PHP4 style constructors for PHP 7 compatibility



  • 19th October 2014
  • Use HTTP HEAD instead of GET to validate API key. More details...



  • 3rd November 2013
  • Plugin is translation ready


  • 5th October 2013
  • Initial version

Why did you create this plugin?

I hate comment spam because it bloats my database. I also don't like bugging my visitors with CAPTCHAs in the form of scribbled text, counting the puppies and answering questions like What is 3 + 2? So when Mailgun released their email validation service I tried validating the email addresses of comments in the spam queue of my blog. I found that nearly 50% of these email addresses were identified incorrect by Mailgun. Thus this plugin was born. Though not as effective as CAPTCHAs this plugin can prevent a decent amount of spam while maintaining user experience.

Is this plugin a product of Mailgun?

No. It only makes use of Mailgun's email validation service API. Nothing in the code belongs to Mailgun.

I get a *401 Unauthorized* error when I verify the API key but I'm very sure that it is correct

You could be using the normal API key, for this plugin you need to enter the Public API Key this is slightly longer than the normal API key and is found just below it.

This plugin is active and I have entered a Valid Public API Key but it doesn't work

Try the email validation demo from the plugin's option page. It could a connectivity issue.

What happens if Mailgun's service is down?

In such cases emails are passed on untouched (as though this plugin is nonexistent) and on the front-end users won't notice anything.

What contact form plugins are supported?

Any form which uses the is_email() function are supported this means the most popular ones like Contact Form 7, Jetpack by, Grunion Contact Form and a lot of others are supported.

Does Mailgun support this plugin?

No, because Mailgun didn't create it. If you need support create a thread by choosing the Support tab of this plugin. If you directly create a thread in the forum I'll never know of its existence.

I want to see a demo of emails validating

Mailgun has created a jquery demo at this page. The code for this demo is available here.

Version 1.2.3

Requires WordPress version: 3.1.0 or higher

Compatible up to: 4.7.2

Last Updated 23 Dec 2016

Date Added: 05 Oct 2013

Plugin Homepage


4.2 stars
21 ratings


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