RFC822: email address validation with regular expressions

Question

as you know, this is how we validate an email address:

(?:(?:\\r\\n)?[ \\t])*(?:(?:(?:[^()<>@,;:\\\\\".\\[\\] \\000-\\031]+(?:(?:(?:\\r\\n)?[ \\t]
)+|\         


        

Answer 1

My policy about email validation is: forget about it. Unicode domains aside, a user can give you a syntactically valid fake address (e.g. test@mailinator.com ).

Instead of validating the email address with that huge (and possibly computationally expensive??) expression

1) send a confirmation link to the user, that way you will know if the email address exist

2) check against Mailinator & Co. domains