Capably Digital Email Validation and Blocklist

This email validation and blocklist plugin makes it easy to set up email blocklists and mx checking on WordPress email functions to reduce bounce rates and unwanted signups.

Features

Email blocklist – This plugin gives you granular control of a blocklist that allows you to stop users from using email addresses that you don’t want them to. Whether you want to block a specific email address or an entire domain, this plugin can handle it.

The plugin also handles prioritising specificity over generalisations, meaning you can block a domain while allowing a specific email address by simply setting the appropriate entries in the blocklist.

MX record checking – Mx records tell the Internet where to send email for a domain, if mx records for a domain you’re sending email to doesn’t exist, it’s generally not worth trying and can result in a hard bounce that affects your sender reputation.

External list synchronisation – There are plenty of lists that you might want to update your blocklist synchronised to, whether that’s a list of disposable email domains or a curated list that your agency maintains. Set the url and let the plugin keep your blocklist in sync by setting up a scheduled job.

Something being blocked by the external list when you don’t want it to be? Just set the domain to be whitelisted, and the synchronisation won’t touch it again, even if it’s in the list.

Logging – Knowing when an email has been blocked is just as important as knowing that emails are being blocked and stopped from being sent. You can choose to log emails that are sent from WordPress and the logs will tell you what failed on which email addresses to help you address issues. The plugin will log all recipients (those contained in the To, Cc and Bcc fields), the checks and results performed on each recipient, and the subject line of the email.

Works with multisite – The plugin is designed to work with multisite, by correctly actioning multisite level actions (activate/deactivate/uninstall etc). This does mean however that all multisite sites are independent of each other. For large multisite installations, using wp-cli or other tools may be required to prevent timeouts as the plugin utilise custom database tables that are created on activation.

Define your settings in wp-config.php – Run a site for someone else or just need to manage your settings for the plugin through something other than the WordPress dashboard? A number of settings can be set by defining constants in your wp-config.php file. If you don’t get a value quite right, we’ll provide a notice for users with the “manage_options” permission on single site installations and “manage_site_options” on multisite.

Expandability – If the plugin doesn’t do what you’re looking for exactly, it also exposes a number of hooks that allow you to change the plugins behaviour to suite your needs. The plugin also exposes API endpoints to allow remote management of the blocklist.

Compatibility

Because our plugin hooks into core WordPress functions, it has extremely wide compatibility, it’s been tested and appears to work with Core WordPress functions, Elementor Forms (via a hook that enables the is_email filter), Contact Form 7, Newsletter, Noptin, WooCommerce, Easy Digital Downloads, LearnPress, bbPress, and BuddyPress. It’s also likely to work with many more that use the filters that WordPress provides.

The notable exception that was found during testing was MailPoet, which does not use the standard filters provided by WordPress, and doesn’t appear to offer a hook that enables integration.

Source Code

The plugin is the source code, there is no (public) repository that contains the “raw” version. What you see is what we work with to create the plugin.