Simulator only gets you so far. A prototype that lives in your hand feels different than one on your trackpad: real iOS 26 Liquid Glass, system haptics, real gestures, real one-handed reach. Test it the way your users will actually use it.
First, get the free Prototo app from the App Store on your iPhone and sign in.
Live preview while you build
In Prototo Desktop, click Preview in the title bar. A QR code drops down. In the Prototo app on your iPhone, tap Scan and point it at the code. Your prototype loads on the phone and picks up changes as you keep describing screens on the Mac. Nothing gets published.
- Same Wi-Fi. iPhone and Mac on the same network. The Preview button becomes active once your project is running.
- Keep Prototo Desktop open. This preview is your live session.
- If macOS asks to allow incoming network connections the first time your phone connects, click Allow.
Using the terminal flow instead? proto start prints the same QR right in your terminal.
Published preview
Run npx proto share (or click Publish in Prototo Desktop) and open the link on your phone: tap it, scan the QR with the camera, or simply copy the link. Prototo notices a copied link when it opens and offers to open it in one tap. This one is published to the cloud, so it works from anywhere and keeps working after you close Prototo. Details in Share your prototype.
A few notes
- iOS 26+. Required for Liquid Glass and other system materials.
- The same app is what people you share with use to view your prototypes.