React Native for Both iOS and Android: How One Codebase Builds Two Apps

Building an app for both iOS and Android usually means double the work. Two teams, two separate codebases, and two sets of updates. React Native changes this. It lets you create robust apps for both platforms using a single codebase, without forcing you into a "compromise app" or a web-view shell.

This blog explains how React Native actually manages to support both iOS and Android, where it works well, and where you still need platform-specific work.

What is React Native?

React Native is a popular framework that uses JavaScript to build real native apps for iOS and Android.

It doesn’t wrap a mobile website inside a native container. Instead, it uses native components under the hood. This means your buttons, lists, layouts, and gestures behave the way users expect on each device giving a seamless user experience.

If you’ve seen apps built with React for the web, the idea is similar, just translated to mobile UI.

Does React Native Work for Both iOS and Android?

Yes, it does.

React Native lets you write most of your app once and run it on both iOS and Android. For many projects, 70-90% of the code is shared.

This shared approach yields significant benefits:

• One Logic Flow: All business rules and data handling are the same.
• One UI Structure: Layouts and screen flows are unified.
• One Team Maintaining It: Updates and bug fixes are applied simultaneously.
• Two Finished Apps: A single effort results in two production-ready apps.

This efficiency is the main reason why companies choose React Native over building two completely separate native applications.

How One Codebase Creates Two Apps (iOS & Android)

React Native relies on three main ideas to execute its cross-platform magic:

1. JavaScript Handles the Logic

Your app’s logic: navigation, data handling, API calls, and state management lives entirely in JavaScript. This is the bulk of the code and is identical for both iOS and Android.

2. Native Components Handle the UI

When you write a React Native component, like <View> or <Text>, it is not a web element. Instead, the framework maps it to the actual UIKit component on iOS or a standard View on Android.

So, even though you write one component using a JavaScript-based syntax, each platform displays its own native equivalent, guaranteeing a platform-appropriate look and feel.

3. A Small Bridge Connects the Two Worlds

The most crucial piece is the JavaScript Bridge. This is a small, highly optimized module that allows asynchronous communication between the JavaScript logic thread and the native UI thread.

• From JS to Native: When the JS thread needs to render a component or call a native feature (like the camera), it sends a message across the bridge.
• From Native to JS: When a user taps a button, the native UI sends an event back across the bridge to update the app's state in JavaScript.

This "bridge" is how your shared code can run on both platforms and still interact with the device's native capabilities.

Where React Native Saves the Most Time

Area	Benefit
Shared Business Logic	Anything that deals with calculations, API calls, authentication, or app data is written only once.
Common UI Screens	Most screens like login pages, forms, shopping lists, or profile pages behave similarly and can reuse the same layouts.
Ecosystem & Libraries	React Native’s strong ecosystem provides ready-made, pre-bridged modules for navigation, storage, permissions, and more, speeding up development.

The combination of these factors is why many teams finish a React Native project much faster than building two separate native apps.

Where Platform-Specific Code is Still Necessary

A shared codebase doesn’t mean everything is identical. Some situations require specialized iOS-only or Android-only code.

You'll need platform-specific work for:

• Deep OS-level Features: Complex device integrations like NFC, Bluetooth, or custom security protocols.
• Heavy Camera Usage: Advanced filters, video editing, or augmented reality (AR).
• Performance-Critical Tasks: Anything that requires near-CPU-level performance, like complex 3D graphics or video processing.
• Custom Native UIs: Integrating a custom native SDK or an unusual UI element that has no React Native equivalent.

Fortunately, React Native supports this. You can write platform-specific files (.ios.js and .android.js) when needed, giving you the flexibility to handle exceptions without abandoning the shared code approach.

What React Native Works Best For

React Native is an excellent fit for applications that are primarily focused on content, data, and standard interactions.

This includes:

• Ecommerce and Retail Apps
• Booking and Travel Apps
• Social Features (chat, feeds, profiles)
• Education and Learning Apps
• Wellness and Fitness Apps
• Community and Marketplace Apps

If your app is mostly screens, forms, lists, and standard interactions, React Native is more than enough.

Performance: How Fast is a Cross-Platform App?

A common myth is that cross-platform apps are slow. This isn't true for React Native.

• React Native apps are not "web wrappers." Because they render real native UI components, the performance is virtually near-native. For everyday apps like shopping, learning, or social features, the difference is rarely noticeable to the end-user.
• Performance issues typically only arise from poor developer practices, such as misuse of re-renders or flawed architecture, not the framework itself. 

With good structure and optimization, React Native apps remain smooth and responsive on both iOS and Android.

Examples of Real Apps Built with One React Native Codebase

React Native is a proven technology used at scale. Here are just a few widely used apps that rely on it:

• Instagram: Used React Native to successfully implement features like the Push Notification Settings and Edit Profile screens, leveraging 70%+ shared code to increase developer velocity across iOS and Android.
• Facebook: The original creator of React Native, they use it for significant portions of their app, particularly for core components and features to ensure a consistent, fast iteration speed across their vast user base.
• Coinbase: Utilizes React Native for their core retail trading app, focusing on component reusability and Fast Refresh to boost development speed while maintaining a high-performance user experience for crucial trading funnels.
• Shopify: Uses React Native for their seller-facing apps and components, enabling merchants to manage their stores efficiently across mobile devices with a unified experience.
• Pinterest (partial): Adopted React Native for key screens like the Topic Picker (used in onboarding) and other flows, achieving a week's worth of time savings by sharing the UI code between platforms.
• Discord (partial): Initially used for its iOS app and later transitioned to Android, they use React Native for their cross-platform interface and logic, which is crucial for managing their massive community chat feeds and rapid feature releases.
• Walmart: Implemented React Native to power major parts of their customer-facing app, including Walmart Pay and in-store features, citing a significant reduction in development time and the ability to share up to 95% of the codebase.

These examples demonstrate that React Native scales well and is suitable for global, high-traffic applications.

React Native vs Building Two Native Apps

A quick comparison:

Aspect	React Native	Two Native Apps (Swift/Kotlin)
Codebase	One	Two separate codebases
Cost	Lower (Fewer developers needed)	Higher (Two specialized teams)
Timeline	Faster	Longer
Maintenance	Easier (One set of updates)	Separate updates and bug fixes
Performance	Near native	Full native
Best For	Most apps (Content, forms, standard logic)	Highly specialized apps (AR, extreme graphics)

Most businesses don’t need the micro-optimization of 100% native code. They need a reliable, fast app that works well on both platforms and can be built in a realistic timeframe. React Native covers that gap efficiently.

The Verdict: One Codebase Truly Delivers Two Native Apps

React Native is arguably the simplest and most effective way to build iOS and Android apps with a single codebase. It significantly reduces development time, cuts cost, and keeps maintenance manageable without sacrificing native UI quality or performance.

If you’re planning to create a mobile app that needs to work reliably on both major platforms, React Native is a practical, modern, and reliable option.

Partnering for Success

While the framework provides the foundation, success lies in expert execution. Companies like Softices, a specialized React Native app development company, help businesses maximize these benefits.

By leveraging their multi-platform expertise, businesses can ensure their shared codebase is architected correctly from day one. Choosing an experienced partner can transform your vision into a successful, dual-platform mobile product efficiently and reliably.