Peek | Devpost

Inspiration

The best part of sharing a photo with a friend is seeing their face when they see it. Messaging apps skip that moment: you send, they look, and you get a "lol" ten minutes later. The iPhone Duo gave us a physical gesture that feels like opening a letter, and we wanted the unfold to be the reveal.

What it does

A friend sends you a Peek, a photo hidden behind a blurred, darkened card.- You reveal it by physically unfolding your iPhone Duo As the hinge opens, the photo sweeps into view, sharpens and brightens in step with the fold angle. A softhaptic fires when the device starts to open, and the reveal completes only when the Duo is fully open.- While you unfold, the front camera records your reaction, so the moment you see the photo is captured.- On the sender side, Your Peek shows each friend who opened it; tap a friend to replay their reaction.- A Friends tab lets you manage who you share with. Peek Plus, a subscription built on RevenueCat, is set up as the premium tier. ## How we built it- SwiftUI on iOS 27.1 with Xcode 27.1 beta, using the Observation framework and a NavigationStack for the inbox, reveal and reactions flows.- iPhone Duo hinge API: a DuoPostureService reads DeviceHingeContext. The hinge angle drives the reveal animation, and the fold status (closed, partially open,fully open) decides when the reveal counts as complete. - AVFoundation:a ReactionCaptureService runs a front-camera AVCaptureSessionand records the reaction with AVCaptureMovieFileOutput. RevenueCat SDK:* a SubscriptionService configures Purchases, loads the currentoffering, watches the plus entitlement through the customer info stream, and exposes purchase and restore.- Bitrig's 3D iPhone Duo simulator let us test fold states before we had hardware.- Liquid Glass*styling across buttons and surfaces.

Challenges we ran into

Making the reveal feel physical: the hinge angle is continuous, but "revealed"needs to be a firm moment. We use the angle for the animation and the discrete fold status as the final say.- Testing without the device: simulators have no camera, so we built a simulated reaction preview and a fallback that fakes unfolding, keeping the whole flowtestable.
Keeping the team in sync: several people were pushing UI changes at once, so webuilt the subscription layer on a separate branch and merged it without touching the screens. ## Accomplishments that we're proud of
The unfold-to-reveal interaction genuinely could not exist on a regular phone.
A clean architecture: posture, camera capture and subscriptions are each their own service, and the UI just watches them.
RevenueCat connects end to end and loads a live offering with a monthly package.

What we learned

How to design around fold states and hinge angles instead of screen taps.
That the physical gesture itself can be the product.
How to integrate RevenueCat entitlements and offerings in a SwiftUI app using the Observation framework.

What's next for Peek

Real sending and receiving between devices, with reaction videos synced to a backend.
Using the outer display so the closed Duo shows "Aish sent you a Peek" and invites you to unfold.
A Peek Plus paywall unlocking longer reaction clips, group Peeks and custom reveal effects.