A prototype is a quickly assembled, working demo of an app that shows off an idea, a screen flow or a key feature - usually so a team or a customer can try it out before deciding whether to keep building. Today's AI app generators (Lovable, Bolt, v0 and similar tools) can turn a single sentence into a usable screen in a few minutes.
The trouble starts the moment a prototype gets used as a production system. It's usually missing three things: a proper data model that can handle a growing team; permissions that decide who can see and change what; and operations - hosting, backups, updates and someone watching over all of it.
That's exactly where the line between a prototype and a production system sits - not in how nice the first screen looks, but in what happens on day 31, when a second user shows up, a new exception appears in the process, or someone needs to be blocked from seeing something.
Related: Lovable, Bolt, v0 and friends: why a prototype never becomes a business system, Template or custom app? A three-question test.