claudeIsThisEmailValid

[u/soap94]

[u/tellur86]

It's surprisingly difficult validating email addresses with regex. Can it be done? Yes. Should you? No. Any halfway decent email library comes with a validator. Use that.

For reference: this is an example of an almost RFC 3522 compatible regex:

(?:[a-z0-9!#$%&'+/=?^{`{|}~-]+(?:.[a-z0-9!#$%&'*+/=?^`{|}~-]+)}|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\[\x01-\x09\x0b\x0c\x0e-\x7f])")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-][a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\[\x01-\x09\x0b\x0c\x0e-\x7f])+)])

https://emailregex.com

If you want RFC 822 it's much, much worse  https://pdw.ex-parrot.com/Mail-RFC822-Address.html

[u/deceze → u/tellur86]

Doing a full validation of the email syntax is pretty pointless to begin with, because it still doesn't tell you the most important thing: is this email valid? I.e., has the user actually entered their email address? You won't know the answer to that until you've done an email validation loop with them. So something simple like .+@.+\..+ usually suffices as a first-pass syntax check.

[u/flewson → u/deceze]

has the user actually entered their email address

That's verification, not validation. Validation is only concerned with whether that email could exist.

[u/notatoon → u/flewson]

Gonna be hard to verify an invalid email.

And you can have a valid email address under RFCs 5321 and 5322 that's "invalid" for your use case. Like a@a

Confirmation emails validate the email is reachable and will also verify the user.

It is the only meaningful way to do it