There are many regexes that validate email, and they usually aren't compliant with the RFC, there are some details in the very old answer on SO. So, better not validate and just send a confirmation, than restrict and lock people out, imo

[–] rumba@lemmy.zip 1 points 6 days ago (1 children)

The article you just mentioned in the comments includes both a completely reasonable and viable regex and binary and library alternatives that are in most languages.

[–] sukhmel@programming.dev 3 points 6 days ago

Reasonable and viable ≠ RFC compliant

This quote summarises my views:

There is some danger that common usage and widespread sloppy coding will establish a de facto standard for e-mail addresses that is more restrictive than the recorded formal standard.

[–] Ephera@lemmy.ml 18 points 1 week ago (1 children)

Well, and remember: If in doubt, send them an e-mail. You probably want to do that anyways to ensure they have access to that mailbox.

You can try to use a regex as a basic sanity check, so they've not accidentally typed a completely different info into there, but the e-mail standard allows so many wild mail addresses, that your basic sanity check might as well be whether they've typed an @ into there.

[–] rumba@lemmy.zip 11 points 1 week ago (1 children)

The regexes are written to comply with RFC 5332 and 6854

They are well defined and you can absolutely definitively check whether an address is allowable or not.

https://datatracker.ietf.org/doc/html/rfc5322

[–] Ephera@lemmy.ml 9 points 1 week ago

Yeah, I'm just saying that the benefit of using such a regex isn't massive (unless you're building a service which can't send a mail).

a@b is a syntactically correct e-mail address. Most combinations of letters, an @-symbol and more letters will be syntactically correct, which is what most typos will look like. The regex will only catch fringe cases, such as a user accidentally hitting the spacebar.

And then, personally, I don't feel like it's worth pulling in one of those massive regexes (+ possibly a regex library) for most use-cases.