Mobile Development6 min read

Expo & React Native

Build and ship iOS/Android apps with Expo - Router navigation, EAS Build, OTA updates, native modules, and device APIs without native code.

ExpoReact NativeMobileiOSAndroid

skill: Expo & React Native category: Mobile Development tags: [Expo, React Native, Mobile, iOS, Android] readingTime: 6

Expo is the best starting point for new React Native apps - it handles the build pipeline, native config, and OTA updates so you can focus on the app. Only eject to bare workflow when you need a native module that Expo SDK doesn't support.

Workflow

Set up a new Expo project with Expo RouterExpo Router brings file-system routing to React Native - the same mental model as Next.js, with deep linking out of the box.
Use Expo SDK APIs for native featuresExpo SDK wraps 50+ native APIs - camera, location, notifications, haptics - without writing Swift or Kotlin.
Build for stores with EAS BuildEAS Build is Expo's cloud build service - creates signed app binaries without needing Xcode locally.
Push OTA updates without app store reviewOTA updates push JavaScript changes directly to users' devices - bug fixes without the 24-48 hour review wait.
Configure native features with app.json pluginsExpo's config plugins modify native Xcode/Gradle projects declaratively - no native project files to manually edit.

Output Format

Expo app: Expo Router for navigation, SDK APIs for native features, EAS Build for store binaries, OTA updates, and config plugins for native permissions.

app/
  _layout.tsx    # root Stack/Tabs layout
  index.tsx      # home screen
  [id].tsx       # dynamic route
eas.json         # build profiles
app.json         # plugins, permissions, store config

Examples

Input

Output

Edge Cases & Gotchas

Managed vs Bare workflow - Managed workflow (Expo Go): easiest, limited to Expo SDK. Bare workflow: ejected to native projects - full native access but requires Xcode/Android Studio.
OTA update limits - OTA updates can only change JavaScript - native code changes (new permissions, native modules) always require a new store submission.
Development builds vs Expo Go - Expo Go has a fixed SDK and can't use custom native modules. Development builds are custom Expo Go-like apps that include your native modules.
New Architecture - React Native's New Architecture (JSI, Fabric) is opt-in as of 2024. Test your Expo SDK version's compatibility before enabling it in production.

When to Break These Rules

Use bare React Native without Expo when you need deep native customization not achievable with config plugins - but only after exhausting Expo's capabilities.
Use Flutter instead of Expo when your team has no React background and cross-platform performance is the top priority.

Reference Files

https://docs.expo.dev/
https://docs.expo.dev/eas/