Confused about custom apps... is there a way to create a web interface in the admin section?

[twilson90]

I've created a 'custom app' in my store, which allows me to send API requests.

I'm just wondering however, is it possible to create a simple web UI in the /admin side of my store for non-developers to use? How would most developers do this?

I've tried creating a public app but that requires a third party to host it, and I'd rather not have to do that for my private custom app.