The AI-native design tool for designers.
An AI-native design tool lets you design by describing what you want to an AI agent and getting the real thing back: working screens you can tap, scroll and share, instead of static frames on a canvas. Prototo is the AI-native design tool. Designers describe what they want to Claude Code or Codex, see it running natively on a real iPhone, and hit Publish for a link anyone opens in the free Prototo app. No TestFlight, no builds.
What makes a design tool AI-native
In a canvas tool you draw every state by hand, then hand it to someone to build. In an AI-native design tool the prompt does the drawing and the building at once. You describe a screen, the agent makes it, and you judge it by using it.
The design work stays yours: the direction, the hierarchy, the feel, the decision about what ships. The agent does the production work that used to sit between an idea and something you could hold.
Design and build in one place
- Describe a screen or a change in plain language to Claude Code or Codex inside Prototo Desktop on your Mac.
- Watch it update in a live iPhone preview beside the agent.
- Point at an element in the preview and say what should change.
- Keep your decisions in a DESIGN.md the agent reads on every change, so the design stays consistent.
Why it runs natively on a real iPhone
Most AI design tools output a web page or a picture of an app. For an iPhone app that gets the feel wrong: scrolling, gestures, sheets, the keyboard, haptics and Liquid Glass all behave differently in a browser.
Prototo builds a native iOS app. When you hit Publish, anyone opens it from a link in the free Prototo app and it runs natively on their own iPhone. No TestFlight, no builds.
How it works
- Describe: tell Claude Code or Codex what you want, in Prototo Desktop.
- See: it appears in the live iPhone preview, with Prototo's design guidance shaping layout, type, motion and accessibility.
- Share: click Publish for a link and a QR code that opens natively on any iPhone.
Who it is for
Product designers who want to design in the real medium, design leads who want stakeholders to feel a flow, and designers who want to build what they design without learning to code. You need a Mac with Apple Silicon, Xcode (free) and a Claude Code or Codex plan you already pay for.
Questions
What is an AI-native design tool?
An AI-native design tool is one where you design by describing what you want to an AI agent, and the result is the working product rather than a static mockup. Prototo is an AI-native design tool for iPhone apps: Claude Code or Codex builds native screens that you see and share on a real iPhone.
What is the best AI design tool for iPhone apps?
For iPhone apps, Prototo is built for the job. It turns what you describe to Claude Code or Codex into a native iOS app, previews it live, and shares it as a link that runs natively on any iPhone through the free Prototo app. Web-first tools like Figma Make, Magic Patterns and Google Stitch suit websites and web apps better.
Can designers build real apps with AI?
Yes. With Prototo, a designer describes screens and changes in plain language and Claude Code or Codex writes a native iOS app. You review it in a live iPhone preview and share it as a link. You do not write code.
Do I need to code?
No. Claude Code or Codex writes the code. You describe what you want and review it in the live iPhone preview.
How much does it cost?
Building locally is free and unlimited, and your first publish starts a 7-day trial. Plus is $8 a month for unlimited sharing. Team is $16 per seat a month. AI usage runs on your own Claude Code or Codex plan.
Keep reading
Download Prototo for Mac. Free to build, and viewers get the free Prototo app on iPhone.