I've been coding for over 20 years now! (WOAH, do I feel old)
I've touched just about every resource imaginable under the Sun (too bad they were bought out by Oracle)
I'd highly suggest NOT using regular expressions for email address syntax validation. The RFC allows for a lot more characters and variance in the email address than what is presented in this particular regular expression, meaning you'll end up excluding some users. And worse, others unaware of this will invariably end up on this article to copy-paste your regex into their application, which will end up them excluding others without even knowing it.
I'd highly suggest NOT using regular expressions for email address syntax validation. The RFC allows for a lot more characters and variance in the email address than what is presented in this particular regular expression, meaning you'll end up excluding some users. And worse, others unaware of this will invariably end up on this article to copy-paste your regex into their application, which will end up them excluding others without even knowing it.
davidcel.is/posts/stop-validating-...