How to Build Your First Mobile App

Build Your First App

This guide gets you from zero to a running mobile app using React Native with Expo — the easiest way to start.

Step 1: Install Expo

npx create-expo-app MyFirstApp
cd MyFirstApp
npx expo start

Step 2: Scan to Preview

Install "Expo Go" on your phone and scan the QR code — your app runs live on your device!

Step 3: Edit the App

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

export default function App() {
  const [count, setCount] = useState(0);
  return (
    <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
      <Text>Count: {count}</Text>
      <Button title="Tap me" onPress={() => setCount(count + 1)} />
    </View>
  );
}

Step 4: Add More Screens

Use React Navigation for multiple screens and navigation between them.

Step 5: Build for Stores

eas build --platform android
eas build --platform ios

FAQs

Do I need a Mac for iOS?

With Expo's cloud builds, no — you can build iOS apps without a Mac. More in our Mobile Development section.

Is Expo free?

Yes — free to start, with paid tiers for advanced builds.