Checks existence of email addresses
To install via npm:
npm install email-existenceA valid email address to check the existence of. Use node-validator to check validity.
Port 25 being allowed for outbound traffic. Digital Ocean in particular blocks that port by default. Check with your hosting provider. If the port is blocked, all emails will report as invalid.
Check existence:
emailExistence.check('email@domain.com', function(error, response){
console.log('res: '+response);
});The check function will return a boolean in response callback function to indicate existence of an email address. Existence is determined by telnetting to the MX server of the email domain and attempting to send an email to the supplied address. MX servers return 250 if the email address exists and 550 if it does not. This test email is not ever sent.