php-email-validator How it works: validate using FILTER_VALIDATE_EMAIL validate using getHostByName validate using FILTER_VALIDATE_IP validate using checkdnsrr validate using dig validate using nslookup Provide Methods: _is_email_valid($email); // bool Note This lib require active internet connection References: https://github.com/egulias/EmailValidator/blob/c81f18a3efb941d8c4d2e025f6183b5c6d697307/src/Validation/DNSCheckValidation.php#L58 https://www.php.net/manual/en/function.getmxrr.php#42396