Custom Form Types

I've suggested previously "ability to validate form types and data inside that field", but I think what I'm trying to look for is customizable form types that way people can have the option to use their external APIs to validate if the answer is true or not true.

The main question is "How do we implement this in the website?", and is being discussed via a thread on the Discord server because there's some limitations on here that don't allow me to post images and code, sorry!