You could also just ask the mail server directly like this: https://gist.github.com/poizan42/2731787 https://gist.github.com/poizan42/2731787 Sure this won't w

You could also just ask the mail server directly like this: https://gist.github.com/poizan42/2731787 https://gist.github.com/poizan42/2731787 Sure this won't work for every SMTP server as some will just "OK" the mail first and send a bounce back later, but neither will the "ask for email twice" approach work every time, and at least it guarantees that the domain exists and has a functioning SMTP server.