MailSure
Sign in

WordPress plugin

Stop fake emails before they reach your list

MailSure checks every email address on your WordPress site, WooCommerce checkout and forms, and refuses the ones that can never receive mail. Visitors get a friendly nudge as they type, with a one-click fix for typos like gmial.com.

Download plugin (v1.0.0)Get a free API key

What it does

  • Blocks the bad ones

    Malformed addresses, domains that do not exist or accept no mail, and optionally disposable and role addresses.

  • Helps the honest typo

    Shows “Did you mean name@gmail.com?” under the field with a one-click fix, before they submit.

  • Never gets in the way

    If MailSure cannot answer, the address is accepted. Results are cached, and your own domains can be allow-listed.

Where it checks

  • WordPress registrationThe standard sign-up form.
  • WooCommerceCheckout and My Account registration.
  • CommentsVisitors who are not logged in.
  • Contact Form 7Every email field.
  • WPFormsEvery email field.
  • Gravity FormsEvery email field.
  • Elementor Pro formsEvery email field.

Using something else? Developers can call mailsure_check_email( $email ) from any code, and we have a REST API and SDKs.

Set up in four steps

  1. 1Download and installDownload the plugin below, then in WordPress go to Plugins, Add New, Upload Plugin and activate it.
  2. 2Paste your API keyCreate a free MailSure account (it includes 100 verifications a month), create a key under API keys, and paste it in Settings, MailSure.
  3. 3Choose what to blockInvalid addresses are always refused. Switch disposable, shared role and likely-typo blocking on or off, and pick which forms to protect.
  4. 4Try itUse the Try an address box on the settings page to see exactly what your settings would do with any address.

Questions

What happens if MailSure is down or I run out of credits?
The address is accepted unchecked and a notice appears in your WordPress dashboard. A verification service should never be the reason a customer cannot check out, so the plugin always fails open.
Does it slow my forms down?
A check normally takes a fraction of a second. Results are cached for a day, so a repeated address is instant and free, and if the service stops answering the plugin backs off for a minute instead of making every visitor wait.
What does it cost?
Each address that gets a verdict uses one credit. Malformed addresses and unknown results are free, and every account includes 100 free verifications a month. Plans and credit packs are on the pricing page.
Can I allow certain domains?
Yes. List your own company domain, or a partner's, under Always allow these domains. They are never checked and never cost a credit.
Does it check that the mailbox exists?
It confirms the address is well-formed, that its domain can receive mail, and whether it is disposable or a shared role address, and it asks the mail server whether the mailbox exists (this works for Gmail, Hotmail/Outlook and most company servers). Yahoo, iCloud and Proton throttle these checks, so for those the mailbox is reported as not checked.
Is the visitor's email sent to you?
Yes: the address being checked is sent to MailSure over HTTPS, and nothing else about the visitor. Mention it in your privacy policy; ours is at mailsure.co/privacy.
Which versions are supported?
WordPress 5.8 and later on PHP 7.4 and later. It has been tested on WordPress 7.1 with WooCommerce 11 and Contact Form 7 6.2.