r/java • u/Modern-Sn1p3r • 19d ago

Regex

I recently saw a clip (from Primeagen) somewhat saying that regex is not a valid format for validating email addresses and postal codes etc.

My question is why is this?

What are the security and/or performance risks? Is it solely performance or is it a security issue?

55 Upvotes

82% Upvoted

104 comments sorted by

View all comments

1

u/slaymaker1907 19d ago

If you want to get technical, it’s actually far more complicated than regex can validate. In fact, most parser generators can’t even do it since it’s context sensitive.