This script is for off line marketers, should be know that email address reaches to a correct sender. That should be overcome with the help of real-time verification system.
when sender sends email via registration form or newsletter, In backend real time verification system is running. When user sends email, this process checks their syntax with retype method and domain check instantly and give message to user that “email is incorrect please send correct email address”. So some spammers cannot enter wrong email address.
So, With real-time verification system, you can ensure that you have a clean list of email address. For API, you should consider online web based email verification providers.
Real-time email verification is when you integrate API provided from Email Hygiene service providers in your website where you collect client details or forms on your website. So if a visitors enters an incorrect email id(typo or something) then the API checks if the email id entered is correct or not. For incorrect email id, you can put up a message such as 'please check the email address' to get valid email id. This Real time email verification process one email address at a time and it takes around a second to verify the address.
So a Real-time email verification makes sure that only correct data is added to your list.