How to design an iPhone app with AI.

You can design an iPhone app with AI by describing it to Claude Code or Codex in Prototo. The agent builds native screens, Prototo's design guidance shapes the layout, type and motion, and you refine it in a live iPhone preview until it feels right. Then you share it as a link that runs natively on any iPhone.

What you need

  • A Mac with Apple Silicon.
  • Xcode, free from the Mac App Store, for the iOS Simulator.
  • Claude Code or Codex, on the plan you already have.
  • Prototo Desktop, free from prototo.app/download.

Steps

  • Start with direction, not screens. Tell the agent what the app is for and how it should feel: "A calm habit tracker, warm and editorial, one habit at a time."
  • Describe the first screen and watch it appear in the live iPhone preview.
  • Judge it by using it. Scroll, tap, open sheets, try dark mode and larger text.
  • Refine one thing at a time. Point at an element in the preview and say what should change.
  • Write your decisions into DESIGN.md (or ask the agent to) so later screens follow them.
  • Add the next screens and the flow between them, then click Publish to share a link.

Design prompts that work well

  • Give a reference and a reason: "a feed like Instagram, because people browse it one-handed".
  • Name the hierarchy: what the one primary action is and what can wait.
  • Describe feel in plain words: "the card settles with a soft spring", "a light haptic on complete".
  • Ask for the states: empty, loading, error and done, not only the happy path.

Keep reading

Download Prototo for Mac. Free to build, and viewers get the free Prototo app on iPhone.