One core flow, clickable and interactive, with real UI, deployed to a live URL. For showing a board, testing with users, or pitching an investor before you build the whole thing.
A prototype is the fastest honest way to see the thing before you pour a build into it. Real UI you can click through, deployed where anyone can reach it, so the feedback you get is about the actual experience, not a slide.
If you already know it's right and want people signing up, start with the Full Build instead.
Tell me about it on a 20-minute fit call.