v0 by Vercel

v0 generates working React and Next.js applications from a text prompt, then plans multi-step tasks — searching the web, connecting to databases, calling APIs, debugging errors — without you writing a single line. The GitHub sync and one-click Vercel deployment mean you skip the part where the prototype dies in a sandbox. The design mode lets non-engineers fine-tune visuals after the AI has scaffolded the structure. The ceiling appears when your app needs custom backend logic beyond what the agent can infer, or when you need to own the full codebase without platform dependency.