iOS is the mobile operating system developed by Apple for iPhone, iPad (until the split into iPadOS in 2019) and iPod touch. Since its first release in 2007, iOS has decisively shaped how mobile devices are used and, alongside Android, is one of the two dominant mobile operating systems worldwide. Internationally, Android leads clearly in market share, but in Germany, the USA and other Western markets, iOS holds a markedly above-average share, especially in the B2B environment, the iOS user base is a particularly relevant audience for many companies.
How is iOS structured?
Like Android, iOS is built as a layered model, but technically rests on an entirely different foundation:
| Layer | Content |
|---|---|
| Darwin/XNU kernel | BSD-Unix-based kernel, hardware abstraction, memory and process management |
| Core OS | Low-level system services, security, file system |
| Core Services | Fundamental frameworks for data management, location services, networking |
| Media | Graphics, audio and video frameworks (Core Graphics, Core Animation, AVFoundation) |
| Cocoa Touch | UIKit and SwiftUI – what developers work with daily |
Every app runs in its own sandbox with strictly limited access to system resources and other apps’ data – a central building block of Apple’s security model.
iOS vs. Android at a glance
| iOS | Android | |
|---|---|---|
| Source code | Proprietary, closed | Core open-source as AOSP |
| Device variety | Apple hardware only | Many manufacturers, broad price range |
| Update distribution | Directly from Apple, high update rate | Via manufacturers, widely varying update duration |
| App distribution | Almost exclusively the App Store (EU exceptions since 2024) | Play Store plus numerous third-party stores, sideloading possible |
| Audience | Traditionally more affluent, strong in DACH/USA | By far the largest global user base |
More on Android’s architecture and development in the Android glossary entry.
Swift and iOS development in detail
iOS apps today are largely developed in Swift, the programming language Apple introduced in 2014 as the modern alternative to the older Objective-C. On the UI framework side, a transition is currently underway: the newer, declarative SwiftUI is increasingly displacing the established, imperative UIKit, but is frequently used in parallel in existing projects. Development happens exclusively with Xcode, Apple’s IDE, which (unlike Android Studio) runs only on macOS – a practical difference that must be considered with mixed development teams. More on our approach on the iOS app development page.
Cross-platform development for iOS
For apps meant to run on iOS and Android simultaneously, a cross-platform framework often pays off instead of two separate native codebases:
- Flutter (Google, Dart) – one codebase, native performance, high-quality UIs on both platforms
- Ionic: hybrid apps on a web stack, well suited to content-centred apps
- React Native (Meta) – the JavaScript/React world with native UI components
Which approach pays off depends on scope, performance demands and existing team know-how.
The App Store and distribution
Apple’s App Store is traditionally the only regular distribution channel for iOS apps – every app passes an Apple review before publication, which secures quality and consistency but also brings approval waiting times. Since 2024, due to the Digital Markets Act, Apple also permits alternative app marketplaces and sideloading in the EU under certain conditions – a tangible break with the traditionally closed model. For digital purchases within an app, Apple charges a commission whose exact rate varies by revenue size, programme and region.
Security and privacy
Apple has positioned privacy as a central selling point of iOS for years: App Tracking Transparency (ATT) has required explicit user consent since iOS 14 before apps may track across devices, the strict sandbox model limits app access to system resources, and many newer AI functions deliberately run on the device rather than in the cloud. For companies processing sensitive user data, that’s a relevant plus over more open platforms.
The 2026 trend: Liquid Glass and Apple Intelligence
With the version jump to iOS 26, Apple switched in 2025 to year-based version numbering oriented on the release year, applied across platforms for iOS, iPadOS, macOS, watchOS and tvOS. Visually, Liquid Glass shapes the current design: a translucent material language reacting to light and motion that runs across app icons, widgets and navigation elements. In parallel, Apple continues to expand Apple Intelligence – on-device AI functions that deliberately run on the device rather than in the cloud, but require newer iPhone hardware. For app developers this means: new projects should factor in the current design system from the start rather than bolting it on afterwards.
Conclusion
Despite smaller global market shares than Android, iOS remains a mandatory target system for most business apps, especially where an affluent, App-Store-affine audience is in focus. Whether native Swift development or a cross-platform framework is the right choice depends on scope, budget and planned platform coverage. More details on our iOS app development page or in an informal chat, with no strings attached.