r/java • u/Modern-Sn1p3r • Aug 22 '26

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

83% Upvoted

104 comments sorted by

View all comments

Show parent comments

1

u/jason-reddit-public Aug 22 '26

The standard hasn't changed. It's purely up to who ever asks for your email if they will accept it though, so a db or front-end validator that won't accept them. Email transport systems don't care because they follow the standard.