[qaisjp]

out of curiosity, why are you trying to validate emails?

[90s_dev]

Just a base level regex before sending emails, to avoid some errors sending to non-email addresses and logging otherwise unnecessary errors.

[esperent]

The best you can hope to do is reduce a small class out of possible errors. But you'll never get a test that can prevent errors like [e-mail], [e-mail], [e-mail] etc. So is it really worth doing any checks at all?

I have a .blue email address and it's amazing how many sites still won't accept it. I keep a spare Gmail account for these.

[bch]

Does this block things like the unconventional Google-filing trick of:

  [e-mail]

which gives me the “90sdev” tag for my emails, which still go squarely into my “[e-mail]” address? I don’t know what the best route is, but I’ve certainly run into bad validators that block things that otherwise work, and that’s annoying. It seems to me the best thing might be to have a user twice input their address, then have the next step/confirmation done via email.

[qingcharles]

Does your regex support emoji usernames and domains? (both of which are in use, e.g. https://mailoji.com/)