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Case study · iPhone and iPad app

Bag Guard. From idea to the App Store.

I made Bag Guard for myself first, so I could leave a bag on the beach or in a locker room without looking over my shoulder. The iPhone inside the bag plays a siren when someone moves it. I did all of it myself, from the first screen to subscriptions and the App Store release.

Coming soon to the App Store
Arming screenAlarm screenGuarding screen

What the app does

What I built

  • An alarm that runs inside iOS Guided Access, so a thief cannot close the app or turn the phone down.
  • Animated instructions matched to the device: measured button positions for 33 iPhone models, the Home button on older ones, the top button on iPad.
  • Subscriptions and a one-time purchase through the App Store, with 3 free armings to start.
  • 10 languages, including store screenshots and preview videos.

What testing taught me

  • Showing it to a friend, the siren played inside a helmet because the phone was paired with a motorcycle intercom. Now the app checks where the sound goes before it arms.
  • A field test at a lake in Kraków showed the alarm started too quickly. Single movements now give a warning, and the siren starts straight away only on the fourth movement within 30 seconds.
  • I did not always make it in time with Face ID. Clicking during a warning now adds 10 seconds.

How it is made

  • Flutter, one codebase that can also go to Android.
  • 62 automated tests guard the core logic: when to warn, when to sound the siren, and what to do when a call comes in during an alarm.
  • No personal data: no account, no own server, no ads. Purchases are verified by Apple through RevenueCat.
  • Terms, privacy policy and a support page written for Apple’s requirements, in Polish and English.

Want an app like this for your business?

I will walk the same road with you: the Apple Developer account, screen design, in-app payments, tests on real phones and release on the App Store and Google Play. Tell me what your app should do and I will reply with a quote.

Bag Guard itself, with videos, setup guide and download, has its own page: bagguard.websly.pl.

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