ReactJS or React Native: Clarifying the Key Differences for Developers

What is ReactJS ?

ReactJS, often simply referred to as React, is a JavaScript library used for building interactive user interfaces for the web. It focuses mainly on the view layer of an application — the part users interact with directly. React introduced the concept of component-based architecture, which means that a UI is divided into independent, reusable pieces called components. Each component handles its own logic and rendering, making code modular and easier to maintain. ReactJS operates using something called the virtual DOM. In traditional web development, when something changes on a web page (say a button click updates some text), the browser re-renders parts of the actual DOM — which can be slow. React’s virtual DOM solves this inefficiency. Instead of manipulating the real DOM directly, React creates a lightweight virtual copy of it in memory. When data changes, React compares the new virtual DOM with the previous version using a process called reconciliation, and only updates the parts of the real DOM that have changed. This approach drastically improves performance and responsiveness. Another key feature of ReactJS is JSX (JavaScript XML), a syntax extension that allows developers to write HTML-like code inside JavaScript. JSX makes code more readable and expressive, blending markup and logic seamlessly.

• Use effects sparingly: Only when side effects are truly needed.
• Keep effects pure: Avoid directly modifying state within effects unless intended.
• Separate logic: Use multiple effects for unrelated tasks.
• Use cleanup functions: Prevent memory leaks from timers or listeners.
• Avoid unnecessary dependencies: Keep arrays minimal and accurate.
• Handle async functions properly: Declare async logic inside the effect, not in the function directly.
• Prevent race conditions: Cancel ongoing requests when dependencies change.
• Document your effects: Clear comments make debugging easier.

By following these principles, developers can write predictable, efficient, and bug-free React components using useEffect.

ReactJS is widely used for building Single Page Applications (SPAs) web apps that dynamically update content without reloading the page. It is often paired with state management libraries like Redux or Context API, and routing tools like React Router, which allow smooth navigation between views without page reloads.

In short, ReactJS revolutionized front-end development for the web by making UIs faster, modular, and easier to reason about.

Are You Interested in Learning More About Full Stack Developer? Sign Up For Our Full Stack Developer Training Today!

What is React Native?

While ReactJS was making waves in web development, Facebook saw a new challenge: mobile development. Creating separate native apps for iOS and Android required two different codebases (Swift/Objective-C for iOS and Java/Kotlin for Android). This doubled development effort and maintenance time. To solve this, Facebook launched React Native in 2015, a framework built on the same React principles but targeting mobile platforms. React Native allows developers to build mobile apps using JavaScript and React, but instead of rendering HTML and CSS in a web browser, it renders native UI components. In React Native, components such as , , and are mapped to actual native components under the hood. This means that an app written in React Native doesn’t run inside a web view — it runs as a true native app, with access to the device’s native APIs and UI performance. React Native achieves this by using a bridge. The bridge is a communication layer between JavaScript and the native environment. When a developer writes JavaScript code, the bridge translates it into native platform instructions. This architecture gives React Native the flexibility of web development with near-native performance.

Developers can also integrate native modules written in Swift, Objective-C, Java, or Kotlin when they need features not available in JavaScript. This hybrid approach makes React Native both powerful and adaptable. With React Native, developers can: Share most of their codebase between iOS and Android. Access device features like camera, GPS, and push notifications. Deliver apps that look and feel native.

Would You Like to Know More About Full Stack Developer? Sign Up For Our Full Stack Developer Training Now!

Platform Focus (Web vs Mobile)

The biggest distinction between ReactJS and React Native lies in the platforms they target. ReactJS focuses entirely on web browsers. It’s used to build websites and web applications that run inside a browser window. It relies on standard web technologies like HTML, CSS, and JavaScript. React Native focuses on mobile operating systems — primarily iOS and Android. It uses native mobile UI components and APIs, providing a more natural mobile experience. Think of ReactJS as building interactive web pages, while React Native builds mobile apps that you install on your phone. Although they share the React philosophy — reusable components, one-way data flow, and declarative UI — their runtime environments are completely different. ReactJS runs in the browser, while React Native runs on the mobile device.

Develop Your Skills with Full Stack Developer Certification Training

Weekday / Weekend BatchesSee Batch Details

Syntax and Component Usage

Both frameworks use components as their fundamental unit of construction. However, the syntax and elements differ due to the environments they run in.

• “`javascript
• import { BrowserRouter, Routes, Route } from ‘react-router-dom’;
• function App() {
• return (
• <BrowserRouter>
• <Routes>
• <Route path=”/” element={<Home />} />
• <Route path=”/about” element={<About />} />
• </Routes>
• </BrowserRouter>
• );
• }
• “`
• React Native uses @react-navigation/native and stack navigators for screen transitions:
• “`javascript
• const Stack = createStackNavigator();
• function App() {
• return (
• <NavigationContainer>
• <Stack.Navigator>
• </Stack.Navigator>
• </NavigationContainer>
• );
• }
• “`

Rendering Techniques

Rendering is where ReactJS and React Native diverge most sharply. ReactJS Rendering: ReactJS uses the virtual DOM to render content in the browser. The virtual DOM is a lightweight JavaScript representation of the real DOM. Whenever data changes, React updates the virtual DOM first, calculates the difference (called a “diff”), and then updates only the changed parts of the real DOM. This minimizes re-rendering and boosts performance, especially in large applications. This mechanism allows ReactJS to provide a seamless user experience, with dynamic interfaces that respond quickly to user input. React Native Rendering: React Native doesn’t use the DOM at all. Instead, it translates React components into native widgets via a bridge. The bridge acts as a translator between the JavaScript thread (where React logic runs) and the native platform thread (which handles rendering and device APIs). When a React Native component renders, it communicates with the bridge to instruct the native platform to render the corresponding native elements. For example, a component on Android may translate to a ViewGroup, while on iOS it becomes a UIView. The bridge architecture provides flexibility but introduces a potential bottleneck if too many messages pass through it. However, with optimizations like Fabric (a new rendering system) and TurboModules, React Native has become significantly faster and more efficient.

Preparing for Full Stack Development Job? Have a Look at Our Blog on Full Stack Development Interview Questions and Answers To Ace Your Interview!

Navigation and Routing

Navigation — moving between different screens or views — also differs based on platform.

React Native Navigation:

Mobile navigation behaves differently. Instead of URLs, apps use stacks and screens. React Native relies on libraries such as React Navigation or React Native Navigation to manage this. These libraries mimic the native navigation experience with gestures, animations, and transitions between screens.

ReactJS vs React Native: Routing Example

>ReactJS uses react-router-dom for client-side routing in web applications:

• “`javascript
• import { BrowserRouter, Routes, Route } from ‘react-router-dom’;
• function App() {
• return (
• <BrowserRouter>
• <Routes>
• <Route path=”/” element={<Home />} />
• <Route path=”/about” element={<About />} />
• </Routes>
• </BrowserRouter>
• );
• }
• “`javascript
• const Stack = createStackNavigator();
• function App() {

While React Router works with browser history, React Native navigation works with mobile navigation stacks — a key architectural difference driven by platform needs.

Access to Native APIs

Access to Native APIs A significant strength of React Native lies in its access to native device features, which ReactJS lacks. ReactJS: Runs inside a web browser and can only interact with browser APIs, such as: LocalStorage for saving small data Fetch or Axios for HTTP requests Geolocation via browser permissions DOM manipulation events However, it cannot directly access mobile hardware features like the camera or accelerometer. React Native: Bridges the gap between JavaScript and native APIs. Developers can use libraries like react-native-camera, react-native-geolocation-service, or react-native-push-notification to interact with hardware components. Additionally, if a specific functionality isn’t available through existing libraries, Full Stack Developer can write native modules in platform-specific languages (Objective-C, Swift, or Kotlin) and expose them to JavaScript. This makes React Native a powerful tool for building feature-rich mobile applications with access to system-level capabilities.

Full Stack Development Sample Resumes! Download & Edit, Get Noticed by Top Employers! Download

Performance Considerations

Performance in ReactJS largely depends on how efficiently the DOM is managed. Thanks to the virtual DOM, ReactJS applications perform well for most use cases. However, for extremely complex UIs with frequent updates, developers might need to optimize rendering using techniques like memoization (React.memo), lazy loading, or avoiding unnecessary re-renders.

React Native, being closer to the hardware, often performs better than hybrid web apps (like those built with Cordova or Ionic). Still, it’s not quite as fast as fully native apps written in Swift or Kotlin. The bridge can become a performance bottleneck if large amounts of data are passed between JavaScript and native threads. Meta has addressed this with the new architecture (Fabric), which streamlines rendering and improves performance consistency.

Use Cases for Each

Code Reusability and Ecosystem One of React Native’s greatest advantages is code reusability. Developers can share a significant portion of their ReactJS code especially business logic and state management between web and mobile applications. Tools like React Native Web even allow React Native components to render in a browser, creating near-universal React codebases. ReactJS boasts a more mature ecosystem with libraries for everything from UI frameworks (Material UI, Ant Design) to testing (Jest, React Testing Library). React Native’s ecosystem, though younger, has grown rapidly, supported by tools like Expo, which simplifies development, testing, and deployment of mobile apps.

Conclusion

ReactJS and React Native are two branches of the same tree — both nurtured by the same React philosophy of modularity, reusability, and declarative UI design. Yet, they bloom in different environments. ReactJS empowers Full Stack Developer to build dynamic, fast, and scalable web applications using components that render in the browser. React Native extends the same logic to mobile applications, translating JavaScript components into native UI elements for iOS and Android. ReactJS runs in the world of the DOM; React Native lives in the realm of mobile APIs. ReactJS speaks HTML and CSS; React Native speaks the language of Views and native styling. Despite their differences, their shared foundation allows developers to transition smoothly between web and mobile development, uniting platforms under one philosophy: learn once, write anywhere. As technology continues to evolve, ReactJS and React Native remain at the forefront of cross-platform development bridging the gap between the web and mobile worlds, one component at a time.