Introduction to React Native

What is React Native?

React Native is a framework, created by Meta (Facebook), that lets you build real native mobile apps for both iOS and Android using JavaScript (or TypeScript) and the React library. The word “native” is important: your code doesn’t run inside a web page. Instead, React Native renders actual native UI components — a React Native <Text> becomes a real iOS UILabel or Android TextView.

How it works under the hood

Your JavaScript runs in a separate engine, and React Native translates your components into native views and talks to native APIs through a “bridge” (modern versions use a faster system called the New Architecture/JSI). The key takeaway for a beginner: you write one JavaScript codebase, and users get a genuine native app on each platform — not a website in a wrapper.

Why teams choose it

• One codebase, two platforms — build iOS and Android together, saving huge time.
• Fast development — “Fast Refresh” updates the app instantly as you save, without losing state.
• Huge ecosystem — it uses JavaScript/React, so millions of developers and libraries are available.
• Native feel — real native components, good performance for most apps.

React knowledge transfers

React Native uses the same ideas as React for the web: components, props, state and hooks. If you know React, you already know most of React Native — you just swap HTML tags (<div>, <p>) for native components (<View>, <Text>).

Your first screen

import { Text, View } from 'react-native';

export default function App() {
  return (
    <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
      <Text>Hello, React Native!</Text>
    </View>
  );
}

Notice all text must be inside a <Text> component — you can’t put bare text inside a <View> like you can in HTML.

React Native vs Flutter vs native

• React Native — JavaScript/React, great if your team knows web tech.
• Flutter — Dart, draws its own pixels (separate course).
• Native (Swift/Kotlin) — maximum performance and platform features, but two codebases.

Common beginner misconceptions

• “It’s just a web view” — no, it renders real native components.
• “I need to know native code” — usually not; you can build complete apps in JS/TS.
• “Performance is bad” — for the vast majority of apps it’s smooth; only very heavy graphics may need native.

Summary: React Native builds genuinely native iOS and Android apps from one JavaScript/React codebase. It renders real native components, develops fast, and reuses your React knowledge directly.