tyingq

I imagine a close typo of a popular domain would also receive a ton of email.

conradludgate

One of the problems we had at my last company were invalid emails. We had so many users enter gnail.com or hptmail.com

tyingq
I use this library for web pages that ask for an email: https://github.com/mailcheck/mailcheck

It's a bit old and requires jquery, but it's fairly easy to gut the library and just use the email logic. It even uses your example of "gnail.com" in the README.