What Is Expo?
Expo is a platform built on top of React Native that provides tools, libraries, and services to simplify mobile app development. It handles the native complexity so you can focus on building your app in JavaScript/TypeScript. As of 2026, Expo is the officially recommended way to start a new React Native project.
Expo is not just a development tool. It is a full ecosystem that includes a framework (Expo SDK), a file-based router (Expo Router), cloud build services (EAS Build), over-the-air update delivery (EAS Update), and app store submission automation (EAS Submit).
Key Components
Expo SDK
A curated set of cross-platform libraries that work out of the box. The SDK includes modules for camera, file system, notifications, location, sensors, authentication, and dozens more. Each module is well-tested against both iOS and Android.
As of Expo SDK 55 (2026), the SDK supports React Native's New Architecture by default.
Expo Router
A file-system based routing library for React Native, similar to how Next.js handles routing for web apps:
- Files in the app/ directory become routes automatically
- Supports nested layouts, dynamic routes, and route groups
- Deep linking is configured automatically based on your file structure
- API routes for serverless backend functions
EAS (Expo Application Services)
The cloud infrastructure side of Expo:
- EAS Build: Build native iOS and Android binaries in the cloud without local Xcode or Android Studio
- EAS Submit: Automate app store submissions to App Store Connect and Google Play
- EAS Update: Deploy JavaScript and asset updates over-the-air without going through app review
Development Workflow
Creating a New Project
Run npx create-expo-app to scaffold a new project. The default template includes Expo Router, TypeScript, and sensible defaults. You get a working app in under a minute.
Development Builds
Expo offers two paths for testing:
- Expo Go: A pre-built app that loads your JavaScript bundle. Great for quick prototyping but limited to Expo SDK libraries only.
- Development builds: Custom native builds that include your specific native dependencies. Built once via EAS Build, then iterated on with fast JavaScript reloads.
Development builds are the recommended approach for production apps because they support any native library.
Prebuild (Continuous Native Generation)
Expo's prebuild system generates the ios/ and android/ directories from your app.json/app.config.js configuration. This means:
- You do not need to manually maintain native project files
- Config plugins modify native code declaratively
- Upgrading React Native versions is dramatically simpler
- Native configuration stays in version control as config, not as generated files
If you need fully custom native code, you can eject from prebuild and manage native directories yourself.
Config Plugins
Config plugins are the mechanism for modifying native project configuration without editing native files directly. They run during prebuild and can:
- Add permissions to AndroidManifest.xml or Info.plist
- Modify build.gradle or Podfile settings
- Add native dependencies
- Configure splash screens, icons, and app metadata
Many Expo SDK libraries include their own config plugins. You can also write custom plugins for unique requirements.
Over-the-Air Updates
EAS Update allows you to push JavaScript and asset changes directly to users without going through the app store review process:
- Updates are downloaded in the background
- Users see the new version on next app launch
- You can target specific platforms, runtime versions, or release channels
- Rollbacks are instant if something goes wrong
This is especially valuable for bug fixes and small feature updates that would otherwise require a full store review cycle.
When to Choose Expo
Expo is the right choice for most React Native projects:
- You want to move fast without wrestling with native tooling
- Cloud builds save you from maintaining macOS build machines
- OTA updates let you iterate without store review delays
- The Expo SDK covers the native modules you need
- File-based routing with Expo Router simplifies navigation
The rare cases where bare React Native makes more sense: highly specialized native integrations, brownfield apps (adding RN to an existing native app), or teams that need full control over the native build pipeline from day one.
Expo in 2026
Expo has matured into the default React Native platform. SDK 55 supports the New Architecture, Expo Router v4 provides robust navigation, and EAS services handle the full build-submit-update lifecycle. The free tier is generous for small teams, and paid plans scale for production workloads.
2026 Current Status
- Expo SDK 55 (February 2026): ships with React Native 0.83, New Architecture always-on
- Legacy Architecture support completely removed in SDK 55
- Hermes v1 available as opt-in
- EAS Build is the standard for cloud-based compilation
- EAS Update for OTA update delivery
- expo-router v4 with file-based routing