Flask validation?

Question

Flask

I use flask_wtf and wtforms.validators to submit the signup form and validate.
When registering, I check the mail, whether it is in the database or not. To do this, I wrote my own validator based on wtforms.validators. He just takes and sees if there is such mail in the database.

This method is generally practiced. what are its downsides. what about security?
What options do you use besides checking in the view function itself?

Answer 1

Validation has nothing to do with security at all. It refers exclusively to business logic.