You can add a feature to check whether a user’s email is fake or true. Using fluentform/validate_input_item_input_email & emailable API. You will need a true mail API key for this. Here is an example of the code:
add_filter('fluentform/validate_input_item_input_email', function ($default, $field, $formData, $fields, $form) {
// You may change the following 3 lines
$targetFormId = 140;
$errorMessage = 'Looks like email is not correct'; // You may change here
$emailableApiKey = 'live_b67c9cb0585e27dd256c';
if ($form->id != $targetFormId) {
return $default;
}
$fieldName = $field['name'];
if (empty($formData[$fieldName])) {
return $default;
}
$email = $formData[$fieldName];
$request = wp_remote_get('https://api.emailable.com/v1/verify?email='.$email.'&api_key='.$emailableApiKey);
if(is_wp_error($request)) {
return $default; // request failed so we are skipping validation
}
$response = wp_remote_retrieve_body($request);
$response = json_decode($response, true);
if($response['state'] == 'deliverable') {
return $default;
}
return $errorMessage;
}, 10, 5);
For details of the hook fluentform/validate_input_item_input_email check this documentation link.