React Native Expo Cheat Sheet: Start, Config, EAS Build & Native Modules

Expo is the fastest way to start React Native: a managed toolchain, Expo Go for JS-only APIs, and EAS Build for store binaries. When a library needs custom native code, you switch to a development build. You do not have to “eject” to a messy bare app to add most plugins.

This React Native cheat sheet is written for people searching for a fast, accurate reference: students, junior developers, and teams shipping production software. Pin it, copy the snippets, and come back when syntax slips.

Quick reference

• Start: npx create-expo-app then npx expo start. Open in Expo Go or a simulator.
• Config: app.json / app.config.js: name, slug, icons, permissions, scheme.
• Expo Go: Great for JS + Expo SDK. Cannot include arbitrary native modules.
• Dev build: expo prebuild or EAS development builds when you add native deps.
• EAS Build: Cloud (or local) production binaries for iOS/Android without owning a Mac for Android-only — iOS still needs Apple accounts.
• Updates: EAS Update / OTA for JS-only changes. Native changes still need a new binary.
• Plugins: Config plugins edit native projects during prebuild. Read the library’s Expo docs.
• Bare: You can add Expo modules to a bare RN app. “Expo vs RN” is a false binary for many teams.

Copy-paste examples

Minimal app.json fields you will touch

Use app.config.js when values come from env. Keep scheme stable for deep links and OAuth.

{
  "expo": {
    "name": "Catalog",
    "slug": "catalog",
    "scheme": "catalog",
    "ios": { "bundleIdentifier": "com.example.catalog" },
    "android": { "package": "com.example.catalog" }
  }
}

Common mistakes

• Adding a native-only library and staying in Expo Go — the module will be undefined.
• Changing icons in JS and expecting the home-screen icon to update without a new native build.
• Committing giant ios/ and android/ folders you generated once and then editing them by hand against prebuild.
• Shipping OTA updates that change native-incompatible code (new permissions, new native modules).

FAQ

1. Is Expo “not real React Native”? It is React Native plus tooling. Production apps on the stores are real native binaries.

1. Do I need a Mac? For iOS simulator and iOS store builds you need Apple’s toolchain or EAS. Android can be fully built on Windows/Linux.

1. When do I eject? Rarely. Prefer a development build + config plugins. Eject/prebuild permanently only if you must own the native projects by hand.

Related React Native cheat sheets

• React Native Cheat Sheet 2026
• React Native Components Cheat Sheet
• React Native Navigation Cheat Sheet

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