React Native: What is It?

What is React Native?

React Native is an open-source mobile development framework created by Meta (formerly Facebook) in 2015. It enables developers to build mobile applications for iOS and Android using JavaScript and the React library, while producing genuinely native interfaces. Unlike hybrid approaches based on WebViews, React Native translates JavaScript components into native platform components, delivering performance close to that of applications built in Swift or Kotlin.

The fundamental principle of React Native is "learn once, write anywhere": a developer who knows React can create mobile applications without learning each platform's native languages. Business logic, state management, and API calls are shared across both platforms, while interface components are rendered as native elements. At KERN-IT, we recommend React Native as our preferred cross-platform solution, thanks to its maturity, rich ecosystem, and natural synergy with our React web expertise.

Why React Native Matters

Mobile development represents a significant investment for businesses. Maintaining two separate codebases (Swift for iOS, Kotlin for Android) doubles development and maintenance costs. React Native solves this equation elegantly.

• Cost reduction: A single development team can target both platforms, reducing the budget by 30 to 50% compared to separate native development.
• Faster time-to-market: Code sharing between platforms enables quicker delivery. Features developed once are available simultaneously on iOS and Android.
• React ecosystem: React web developers can contribute to the mobile project without a steep learning curve. React libraries and patterns are directly reusable.
• Hot Reloading: Hot reload lets developers see changes in real time during development, without recompiling the entire application. This dramatically accelerates development cycles.
• Native performance: React Native components are compiled into platform-native elements, providing a smooth and responsive user experience.
• Massive community: With millions of monthly downloads and Meta's backing, React Native benefits from one of the richest library and tooling ecosystems in the mobile market.

How It Works

React Native relies on a bridge architecture that enables JavaScript code to communicate with the platform's native modules. Developers write React components in JavaScript or TypeScript. These components describe the desired interface declaratively. The framework then translates these descriptions into native calls: a View component becomes a UIView on iOS and an android.view.View on Android.

Since 2022, the new architecture (Fabric and TurboModules) has profoundly modernised this mechanism. The asynchronous bridge has been replaced by a synchronous C++ interface (JSI - JavaScript Interface), which eliminates JSON serialisation and significantly improves performance. Fabric handles interface rendering more efficiently, while TurboModules enable lazy loading of native modules.

At KERN-IT, we structure our React Native projects with TypeScript for type safety, Redux or Zustand for state management, and React Navigation for routing. We use Expo as a development environment when the project does not require custom native modules, which greatly simplifies configuration and deployment.

Concrete Example

Consider a Brussels-based SME in the meal delivery sector that wants to offer a mobile app to its customers and delivery drivers. Developing two separate native applications (iOS and Android) for each user profile would mean four distinct projects, representing a considerable budget.

With React Native, the company develops a single application where 85% of the code is shared between iOS and Android. The customer app allows ordering, real-time delivery tracking via geolocation, and online payment. The driver app displays available deliveries, optimises routes, and manages push notifications. The only platform-specific parts concern native payment integrations and background location permissions. The project is delivered in 3 months instead of 6, with a single team of 3 developers.

Implementation

1. Initialise the project: Use Expo CLI or React Native CLI depending on project needs. Expo is recommended for standard projects, the native CLI for projects requiring custom native modules.
2. Structure the architecture: Organise code in layers (UI components, business logic, API services) to facilitate maintenance and code sharing.
3. Configure navigation: Set up React Navigation with appropriate navigators (stack, tabs, drawer) based on the desired user experience.
4. Manage application state: Choose a state management solution (Redux, Zustand, React Context) based on application complexity.
5. Integrate native modules: Configure platform-specific modules (push notifications, geolocation, camera, payments) via community libraries or custom modules.
6. Test on both platforms: Use Jest for unit tests, Detox or Maestro for end-to-end tests, and test on physical devices to validate real-world performance.
7. Deploy: Configure build pipelines for iOS (App Store) and Android (Google Play) via EAS Build (Expo) or Fastlane.

Associated Technologies and Tools

• Expo: Development platform that simplifies creating, building, and deploying React Native applications.
• TypeScript: Typed superset of JavaScript that improves code reliability and the development experience.
• React Navigation: Standard navigation library for React Native, flexible and performant.
• Redux / Zustand: State management solutions for complex applications.
• Fastlane: Build and deployment automation tool for mobile app stores.
• Detox / Maestro: End-to-end testing frameworks for validating application behaviour on real devices or simulators.

Conclusion

React Native has established itself as the go-to solution for cross-platform mobile development. Its ability to produce genuinely native applications from a single JavaScript codebase makes it a strategic choice for businesses wanting to reach iOS and Android users without doubling their investment. At KERN-IT, we recommend React Native as the first option for our Belgian and European clients' mobile projects, complementing our React web expertise. The new architecture and the Expo ecosystem continue to strengthen React Native's position as a pillar of modern mobile development.