I think the point of the article is that this seems like it would be an easy problem to solve, but it is not. Lots of commenters insisting that they need to va

I think the point of the article is that this seems like it would be an easy problem to solve, but it is not. Lots of commenters insisting that they need to validate somehow. If you have a need to validate, use a good email validation library. Better consistency throughout your app, and someone else has figured out the hardest stuff. Stop validating emails. But if you can’t stop, at least stop rolling your own regex on the fly to do it. Use a good library instead.