Android and iOS are two different mobile operating systems, each with its own unique features and functionalities. Therefore, there are some differences between the two when it comes to developing proprietary mobile applications.

Here are some of the key differences:

1. Development Language: Android apps are typically written in Java or Kotlin, whereas iOS apps are written in Swift or Objective-C.
2. User Interface: The user interface (UI) of Android and iOS apps are different. Android apps typically have a more customizable and flexible UI, while iOS apps follow Apple’s design guidelines and have a more consistent look and feel.
3. App Store: Android apps are distributed through the Google Play Store, while iOS apps are distributed through the Apple App Store. Each store has its own review process and guidelines that developers must follow.
4. Fragmentation: Android has a more fragmented ecosystem due to the variety of devices and operating system versions that exist. This can make it more challenging to ensure app compatibility across all devices. iOS has a more closed ecosystem, with fewer device options and a more consistent operating system.
5. Hardware Integration: iOS apps have more access to hardware features such as the camera, microphone, and touch ID, making it easier to develop apps that make use of these features. Android apps have access to these features as well, but there may be more variability in how they work across different devices.
6. Development Tools: Android development requires the use of Android Studio, which is available on Windows, Linux, and macOS. iOS development requires Xcode, which is only available on macOS.

In summary, while Android and iOS have some similarities in terms of mobile app development, there are significant differences in terms of development language, user interface, app store, fragmentation, hardware integration, and development tools. Developers must take these differences into account when creating a mobile app for a specific platform.