EAS Build/Submit/Update & Cross-Platform Tradeoffs

EAS Build — Cloud Native Compilation

EAS Build compiles native iOS/Android binaries on Expo's cloud infrastructure, notably removing the hard requirement of owning a Mac for iOS builds. EAS Submit then automates uploading the built binary to the App Store or Play Store via CLI, rather than manual upload through Xcode/App Store Connect or the Play Console.

EAS Update — Shipping Without App Store Review

Over-the-air updates push new JS/asset bundles directly to installed apps, bypassing a full app store review cycle — but only for changes that don't touch native code. Any actual native dependency change still needs a new EAS Build and submission.

Config Plugins & expo install

A config plugin customizes the native project generated by prebuild (e.g. modifying an Android manifest or iOS Info.plist) declaratively in JS/JSON, so it survives regenerating native folders rather than requiring hand-edits that prebuild would wipe out. expo install (instead of a plain npm/yarn install) installs the version of a package known compatible with the project's current Expo SDK, avoiding subtle native-vs-JS version mismatches.

SDK Upgrades & expo doctor

An Expo SDK version bundles interdependent React Native and native module versions together, so upgrading it is more like a coordinated stack upgrade than bumping one library. expo doctor diagnoses common project configuration issues — like dependency versions mismatched against the installed SDK — before they cause confusing build failures.

The Cross-Platform Tradeoff

A shared JS/TypeScript codebase targeting both iOS and Android reduces duplicated effort versus fully separate native Swift/Kotlin codebases, at the cost of some platform-specific customization flexibility and occasional native-bridging friction. React Native Web (which Expo integrates with) extends that further, letting UI code run in a browser for faster iteration and devtools-friendly debugging alongside the mobile targets.