Your interface was drawn for one iPhone. Send us a simulator build and we check your app's main everyday flows across the cover and inner displays, with targeted dark-mode and large-text checks. We show you whether it runs full screen or letterboxed in a compatibility window, whether a task in progress survives opening and closing the phone, and look for fixed widths, custom bars and controls in the side column that ignore the Duo's layout, graded against Apple's Human Interface Guidelines and Apple's iPhone Duo guidance, whatever your app does. Your report states exactly what was tested.
Works with React Native · Native (Swift, SwiftUI, UIKit) · Flutter · Expo
iPhone Duo doesn't scale your interface, it re-composes it. On the cover screen, an app built with an older SDK runs in a smaller compatibility window, and layouts built on fixed frames and one-size assumptions look out of place. Your app won't crash. It will just look unfinished.
An app built with an SDK older than iOS 27.1, or one that doesn't fill the display, runs in a phone-sized window with black around it. Every report says which mode yours ran in, and that the layout checks don't apply in that window.
Containers fixed at a classic iPhone width, or held narrow with wide margins, leave dead space on the Duo's display. When your app runs full screen, we look for them on every screen we capture.
iPhone Duo stands system bars upright at the side of the cover screen. When your app runs full screen, we check for buttons that reach into that column, custom bars that won't move there and text-only bar items.
Portrait-only orientations and UIRequiresFullScreen limit how iPhone Duo can show your app. We read them from your build's Info.plist.
It's the first impression. Owners try their favourite apps on a new device first. A letterboxed, phone-shaped layout says nobody looked.
It's on the record. Screenshots of broken layouts travel fast, and reviews remember them long after the fix ships.
It's cheaper now. Most of these are small changes once someone shows you where they are. Found late, they arrive as one-star reviews.
Closed and open: we follow your app's main journeys on the cover screen, and at the first screen and at tasks left unfinished (a search typed, a form half filled, a list scrolled) we open the phone, capture the inner display, and close it again to see that the task is still there. These are layout and continuity checks: we don't tap on the inner display, and we don't record the fold animation itself or half-open poses. Every report says where we opened the phone and what happened.
A bigger canvas also magnifies what was quietly wrong all along. Your team checks the app in one appearance and one text size. Your users don't. We check for these on chosen screens of each journey, too.
Hard-coded colours turn into grey text on black, invisible icons and white flashes between screens.
Labels truncate, buttons overlap and fixed-height rows clip their content when Dynamic Type is turned up.
Unlabelled buttons, file names read aloud and tap targets smaller than 44 points.
Zip the .app from a simulator build and drop it on your private upload link. Your browser checks it in seconds, and big uploads resume if the connection drops.
A fresh simulator of each phone you picked installs your app, records its launch and follows its main everyday journeys, capturing each distinct screen with its accessibility tree, and chosen screens in dark mode and at the largest text size. On iPhone Duo it starts closed, on the cover screen, and opens the phone at the first screen and at tasks left unfinished.
Every finding has a severity, the screen it's on, what we saw, why it matters and the HIG principle it rests on, with the fix, the effort and an order of work.
What a finding looks like. An example, not a client's app.
What we captured · accessibility tree, largest text
At the largest text size the summary grows and pushes "Pay now" off the bottom of the screen with no scroll view, so the purchase can't be finished. HIG · Layout: keep primary actions reachable at every text size.
Fix: put the summary in a scroll view and pin the button to the safe area. Effort: small.
VoiceOver reads "button". HIG · Accessibility: give every control a label VoiceOver can speak.
Fix: accessibilityLabel="Close" and a 44 × 44 pt hit area.
A banking app, a marketplace and a weekend side project get the same audit, because Apple's Human Interface Guidelines are the standard your users already expect. Every finding names the HIG principle it rests on, and the iPhone Duo checks follow Apple's own Designing for iPhone Duo guidance for the cover screen, where the audit runs. We don't grade against a house style or one industry's habits.
Each finding names the Human Interface Guidelines principle it rests on, or Apple's iPhone Duo guidance, with the evidence. Where the HIG points to a measurable threshold, such as contrast, we use WCAG 2.2 AA.
Recommendations come with implementation notes for React Native, SwiftUI, UIKit or Flutter.
No source code needed. We only run your build, never decompile or share it, and delete it as soon as your report is ready.
Early access We're taking a small number of teams while we open up. Your first review is free: reserve a spot and there's nothing to pay. Reviews after that are priced per app, as below.
$399 per app reviewEarly access: your first review is free
Best for: getting ready for iPhone Duo.
$249 per app reviewEarly access: your first review is free
Best for: knowing where you stand before a release.
$499 per app reviewEarly access: your first review is free
Best for: teams who ship to every iPhone.
Fixed what we found? A re-review of the same app within 30 days of its report is $99, on the same phones. Prices are in US dollars. We email the report in about a day. If an audit fails on our side or your app won't open in the simulator, you pay nothing: see the refund policy.
Want us to fix the findings too? Fixes as pull requests are coming soon.
Already have an upload link? Open it to send your build.
Because it's where layouts built for one phone shape are most exposed. Apps that look polished on a regular iPhone can run on the Duo's cover screen letterboxed, with fixed widths and controls in the way of the side column. The audit shows you where, with the fix for each finding. We follow your main journeys closed, on the cover screen, and open the phone at the moments that matter.
Yes, if it's an iPhone app. We audit against Apple's Human Interface Guidelines and iPhone Duo guidance, which apply to every category, so a ten-screen utility and a fifty-screen marketplace are held to the same standard. The report notes what the walkthrough couldn't reach, such as screens behind a purchase.
Yes, in early access. We open private upload links to a few teams at a time. Reserve a spot and we'll email you when yours is ready.
A review is $399 on iPhone Duo, $249 on a standard iPhone (tested on iPhone 18 Pro), or $499 on both, and every review includes a recommended fix for each finding. A re-review of the same app within 30 days of its report is $99. During early access your first review is free. If an audit fails on our side or your app won't open in the simulator, you aren't charged, or you get your money back (refund policy).
Device builds can't run in the iOS simulator. A simulator build is one command from Xcode, Flutter or Expo, and our upload page shows you exactly which one.
Not for the audit or recommendations: we only need the build. Fixes as pull requests, when they launch, will need access to your repository.
The ones your users rely on most. After recording the launch, an automated walkthrough picks up to three main everyday journeys in your app and follows them until each is done or blocked, tapping, scrolling, typing and signing in with your test login the way a user would, and captures each distinct screen along them, up to twenty per phone, with dark mode and the largest text size on chosen screens. It is told never to buy, send, delete or change account details, and it refuses any control labelled to buy, pay, send, share, delete or sign out. Every report lists exactly which screens were captured and how.
Your build goes straight to private storage, encrypted at rest, and runs only in a fresh simulator on a Mac that GitHub creates for the run and destroys afterwards. We never decompile, disassemble, modify or share it, and we delete it as soon as your report is ready, within 7 days at most. A test login is encrypted in your browser with a key only our audit system holds, is typed only into the simulator, and is deleted when the audit run ends. We sign your NDA on request. The privacy policy has the details.
React Native (including Expo), native Swift with SwiftUI or UIKit, and Flutter. Recommendations come with notes for the framework your app is built in.
Real-device performance, haptics, the camera, Apple Pay and push notifications from Apple's servers. Every report says so, and we never guess at them.