After reading the README twice I still don't know what it does or if I could have any need for it. What about a more concrete exmaple in the README?

The demo is more speaking. And the tool looks actually interesting.

How about:

    With StIGMA you can create a web form GUI from an example JSON object (demo-link).

    Example:
    x = { "name":"John Smith", "age":24 }; # Make it simple
    gets translated to 
    y = ...
    which can be rendered on a webpage as:
    [Screenshot]

Then later describe the process in detail.