Gravity Block Disposable email

code.php

<?php
add_filter('gform_field_validation', 'check_disposable_email_gf', 10, 4);

function check_disposable_email_gf($result, $value, $form, $field) {
    if ($field->get_input_type() !== 'email' || empty($value)) {
        return $result;
    }

    // Exact domain blocklist
    $blocked_domains = [
        'emailnow.net',
        'tempmail.net',
        '10minutemail.com',
        'mailinator.com',
        'guerrillamail.com',
        'trashmail.com',
        'fakeinbox.com',
        'maildrop.cc',
        'getnada.com',
        'dispostable.com',
        'yopmail.com',
    ];

    // Partial MX host blocklist (substring match)
    $blocked_mx_substrings = [
        'anonymmail.net',
        'emailnow.net',
    ];

    // Get domain from email
    $domain = strtolower(substr(strrchr($value, "@"), 1));

    // Block if domain is exactly in the list
    if (in_array($domain, $blocked_domains)) {
        $result['is_valid'] = false;
        $result['message'] = 'Sorry, we do not accept temporary email addresses.';
        return $result;
    }

    // Check MX records for partial match
    $mx_records = dns_get_record($domain, DNS_MX);
    foreach ($mx_records as $record) {
        if (isset($record['target'])) {
            foreach ($blocked_mx_substrings as $blocked_mx) {
                if (stripos($record['target'], $blocked_mx) !== false) {
                    $result['is_valid'] = false;
                    $result['message'] = 'Sorry, we do not accept email addresses from disposable services.';
                    return $result;
                }
            }
        }
    }

    return $result;
}