Platforms and Operating Systems in Mobile Development: What They Are, Architecture, and How They Work

What Is a Mobile Operating System?

A mobile operating system (Mobile OS) is the core software that manages the operation of a smartphone or tablet: it launches applications, allocates memory, processes touch input, and provides access to hardware functions (camera, GPS, sensors). Each mobile OS provides developers with an API — a set of ready-made functions for interacting with the device.

Android is built on the Linux kernel and is an open-source project (AOSP). Any manufacturer can freely use and modify the code. According to StatCounter as of June 2025, Android is installed on more than 3.9 billion devices worldwide. In contrast, Apple's iOS only runs on Apple devices and has closed-source code.

For a developer, choosing a platform determines the programming language, development tools, and distribution market. At IT Sectr, we have been developing applications for both platforms since 2017, and our experience shows: it is easiest to start with Android and then learn iOS.

Types of Mobile Operating Systems

The mobile operating system market is not limited to two giants. Besides Android and iOS, there are other platforms, each occupying its own niche.

iPadOS is a version of iOS adapted for the large iPad screen. It supports multitasking, keyboard input, and Apple Pencil. watchOS and tvOS are Apple platforms for watches and TV set-top boxes. HarmonyOS from Huawei runs on smartphones, tablets, and smart devices. KaiOS is a lightweight OS for affordable feature phones. Samsung's Tizen is used in smartwatches and televisions.

According to StatCounter (2025), the combined share of all platforms other than Android and iOS is less than 1%. For a developer, this means: focus on Android and iOS, and consider other platforms as additional if the market or task requires it.

Android vs iOS: Key Differences

Android and iOS differ in many parameters that matter to a developer: market share, development language, tools, and store policies.

Android is great for beginners: no Mac needed to get started, developer account costs $25 once. iOS provides higher ARPU (average revenue per user) and less device fragmentation. At IT Sectr, we develop apps for both platforms and have noticed: iOS users make in-app purchases 2–3 times more often.

Other Platforms: HarmonyOS, KaiOS, Tizen

In addition to the two main platforms, there are specialized operating systems on the market, each with its own target audience and ecosystem.

HarmonyOS from Huawei was launched in 2019 as a response to US sanctions. It supports Android apps through compatibility and has its own AppGallery store. According to Counterpoint Research (Q1 2025), HarmonyOS holds about 4% of the market in China.

KaiOS accounts for about 0.3% of the global market but is popular in developing countries (India, African countries). Applications for KaiOS are developed using HTML/CSS/JavaScript. Tizen is used in Samsung Galaxy Watch smartwatches and Samsung televisions.

If you are just starting your journey in mobile development, do not spread yourself thin over niche platforms. Start with Android or iOS — they cover 99% of the market and offer the best career opportunities.

SDK, API Level, and Platform Versions

SDK (Software Development Kit) is a set of libraries, tools, and documentation that allows you to develop applications for a specific platform. Without an SDK, mobile platform development is impossible.

For Android, key concepts are API Level (integer identifier of the API version): minSdkVersion (minimum version the app will run on), targetSdkVersion (version the app is optimized for), and compileSdkVersion (version used during compilation). According to Google (Android Studio May 2025), setting minSdkVersion to API Level 24 (Android 7.0) covers 95% of active devices.

For iOS, the equivalent concept is iOS Deployment Target (minimum iOS version for running the app). NDK (Native Development Kit) allows writing C/C++ code for Android — this is needed for performance-intensive tasks: video processing, computer vision, Unity/Unreal Engine games.

// build.gradle — пример конфигурации SDK
android {
    compileSdkVersion 34
    defaultConfig {
        applicationId "com.example.myapp"
        minSdkVersion 24
        targetSdkVersion 34
    }
}

The code above sets SDK versions for the project: compilation uses API 34, minimum for launch is API 24, and target version is API 34. This approach allows using the latest platform features during compilation while maintaining compatibility with older devices.

Emulators and Simulators for Testing

For testing mobile applications without real devices, emulators and simulators are used. These tools mimic device operation on the developer's computer.

Emulator for Android fully models device operation: it uses ARM translation, allows testing screen rotations, calls, GPS, and sensors. AVD (Android Virtual Device) is a configuration of a specific device in the emulator that you set up in Android Studio.

Simulator for iOS, unlike the emulator, does not execute ARM code natively. It only runs on Mac and uses the computer's CPU for execution, so it cannot test some hardware features. According to IT Sectr's experience, we recommend testing on real devices before release, but during development, the emulator or simulator covers 90% of tasks.

App Stores: Google Play and App Store

Google Play and App Store are the only official channels for distributing mobile applications. Each has its own publishing rules, quality requirements, and review procedures.

Google Play accepts apps in AAB (Android App Bundle) format, the review is automated and usually takes a few hours. The developer account costs $25 once. App Store accepts IPA files through App Store Connect, the review is manual and can take from a few hours to several days.

Store rules are regularly updated. According to Statista (2026), the App Store has more than 1.8 million apps, and Google Play has more than 2.5 million apps. Before publishing, carefully study the rules of the specific store — rejection leads to publication refusal and loss of time.