Using the App checker

Native apps can't run inside a web page the way a website can, so the App checker gives you three ways to test an app instead. Pick the one that matches what you have.

1. Screenshots

Best when you have screenshots from a simulator, emulator or real device. Nothing is uploaded — images are processed in your browser.

1. Drag screenshots onto the drop zone, click it to browse, or paste an image with Ctrl+V. Up to 12 at a time; click a thumbnail to switch.
2. Choose devices from the chips (up to 6). Each one frames your screenshot at its real aspect ratio.
3. Leave 🟥 Safe areas on. Red bands mark the status bar, notch / Dynamic Island / punch-hole camera and the home-indicator area. Anything important inside a red band is at risk of being hidden.
4. Use Fill to crop the screenshot to each device, or Fit to letterbox it. Under each frame you'll see whether the aspect matches or how much is being cropped.

Store readiness

For the selected screenshot, AKCLNT Responsive Checker checks the App Store accepted sizes and the Google Play rules (format, 320–3840 px sides, maximum 2:1 aspect ratio, 8 MB) and tells you which device the screenshot probably came from. See the full table in App Store & Play Store screenshot sizes.

Mockup PNG

⬇ Mockup PNG under any frame downloads your screenshot inside a phone frame with a soft shadow — ready for a store listing, a portfolio or a client presentation.

2. Native app (APK / IPA)

To click through a real build on several devices, AKCLNT Responsive Checker embeds Appetize.io, which streams your app from cloud simulators and emulators.

1. Upload your .apk (Android) or a zipped iOS simulator .app at appetize.io/upload.
2. Copy the public app link, for example https://appetize.io/app/abc123.
3. In the Native app tab, paste the link, choose Android or iOS (it must match your build), pick up to three devices and an orientation, then press Load app.
4. Press Tap to play on each device.

3. Web app / PWA

If your app has a web build — Flutter web, Expo / React Native Web, Ionic, or a PWA — paste its URL in the Web app / PWA tab and it opens in the main checker on five phones and a tablet. The tab also lists the build and tunnel commands for each framework.

Fixing what you find

Filter Issues & Fixes by 📱 App to see app-specific problems — safe areas, the keyboard covering inputs, hard-coded sizes, large system fonts, tablets and orientation — each with Flutter, React Native and Android code. The safe area & notch guide goes deeper.