You're correct that Prototyper is generally used for frontend and design work. It's not a tool that’s available directly in a Node.js environment, as it's more geared towards frontend prototyping and visualizing the application flow before integrating the backend. If you want to build prototypes with Node.js backend features (such as role management, authentication, etc.), you'll have to use a combination of tools for the rapid development and design of the backend and frontend.