Skip to main content

Check if email already exists in WordPress

Overview​

When building custom forms or integrations in DataPress, you may need to quickly check whether a specific email address already belongs to a registered WordPress user. This is especially useful for conditional rendering, validation, or preventing duplicate registrations.

This guide shows how to expose a custom Twig function called wp_email_exists that performs this check using WordPress internals.

Add the Function to Twig​

Add the following PHP code to your theme’s functions.php file or a custom plugin:

add_filter('integration-cds/twig/functions', function (array $fns) {
    $fns['wp_email_exists'] = new Twig\TwigFunction('wp_email_exists', 
      function (string $email): bool {
        $email = sanitize_email($email);
        return is_email($email) && (bool) email_exists($email);
      }
    );
    return $fns;
}, 10, 1);

This registers a new Twig function `wp_email_exists` that:

- Sanitizes the input email
- Validates its format
- Checks if the email exists in the WordPress user database

### Usage in Twig Template

Once registered, you can use the function directly in your form or template logic:

```twig
{% if wp_email_exists('test@example.com') %}
  <div class="alert">This user already exists!</div>
{% endif %}

This will conditionally render the alert only if the email is already associated with a WordPress user.

note

This is server-side functionality. It can only be used to validate data already submitted.