Creating forms from a script/json structure?

This is quite a theoretical question and I'm interested in possible solutions / advice if possible. I'm looking into creating an app for displaying details after a form is submitted. Now that's all fine, but what I also want is the ability for someone to be able to easily create a form for the input, without them having to write any actual code. I've looked into drag and drops etc but I'm interested in the idea of having then write a structure (in json I guess) and then a form being generated. The form could have many possible functionalities ( ie dropdowns, select boxes, upload files ) as well as them being able to specify decencies and rest end points to populate the fields.

Anyone come across anything similar or have any suggestions? It would be greatly appreciated. Sorry if my question lacks any cohesion, thanks :)