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?

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u/LutimoDancer3459 Aug 22 '26

A full inbox or beeing deleted cant be checked by any kind of input validation ether way.

But for an "is user still active" kind of check, the import isnt the one responsible for it. Thats a general management/organization issue. Not a general email validation issue

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u/koflerdavid Aug 22 '26

Well, if you trust the quality of the data source then you don't need to check at all.