Can I change my app's package name after publishing on Google Play?

No. The applicationId is the permanent unique identifier of a published app — Google Play does not allow changing it. You would have to publish a brand-new listing and lose your reviews, downloads, and ranking. The same applies to the iOS bundle identifier on the App Store.

What is the difference between applicationId and namespace in Android?

The applicationId in build.gradle is the unique store identifier users see in the Play Store URL. The namespace is the Java/Kotlin package for your R class and activity classes — they can differ, and in modern projects they usually do.

Where do I set the package name in Expo?

Set expo.android.package and expo.ios.bundleIdentifier in app.json (or app.config.js), then run npx expo prebuild --clean to regenerate the native projects. Never edit the generated ios/ and android/ folders directly when using Continuous Native Generation.

How to Change the Package Name in React Native & Expo (Safely)

Renaming your app's package name is trivial before you publish and effectively impossible after — Google Play and the App Store treat applicationId / bundleIdentifier as the permanent identity of a published app. Here is the safe order of operations for both Expo (managed workflow) and bare React Native.

The rule that matters most

You cannot change the package name after publishing. Renaming means publishing a new app — losing your reviews, download history, and store ranking. Get it right before your first release.

Choose a package name you control forever: the reverse-domain of a domain you own (com.yourcompany.yourapp), lowercase, no hyphens.

Expo (managed workflow / CNG)

If you use Continuous Native Generation (no committed ios/ and android/ folders), there is exactly one place to change:

{
  "expo": {
    "android": { "package": "com.yourcompany.yourapp" },
    "ios": { "bundleIdentifier": "com.yourcompany.yourapp" },
    "scheme": "yourapp"
  }
}

Then regenerate the native projects:

npx expo prebuild --clean

--clean matters — it wipes and regenerates ios/ and android/ so no stale identifiers linger in build.gradle, the manifest, or the Xcode project.

Also update while you're at it:

expo.scheme — your deep-link scheme (see the deep links guide).
Firebase config (google-services.json / GoogleService-Info.plist) — bound to the package name.
Push notification credentials, if they reference the old bundle ID.

Bare React Native

Without CNG, you own the native projects directly. Android first:

android/app/build.gradle — change applicationId "com.oldname.app" (and optionally the namespace).
Package structure — rename the Java/Kotlin folders under android/app/src/main/java/com/oldname/... and update MainActivity / MainApplication declarations.
AndroidManifest.xml — update the .MainActivity path if the package changed.

Then iOS:

Open the Xcode project and change Bundle Identifier on every target (app, tests, widgets).
Or edit PRODUCT_BUNDLE_IDENTIFIER directly in project.pbxproj.

Finally, rebuild clean — stale derived data caches old identifiers:

cd ios && pod deintegrate && pod install && cd ..
npx react-native clean && npx react-native run-android

The checks people forget

Play Console draft — if you already created a draft listing with the old package, delete it before uploading a new AAB.
Deep links and universal links — the package name is part of Android App Links; your assetlinks.json and iOS AASA files must match the new identifier.
Sentry / analytics / AdMob — SDK configs often embed the package name; regenerate them after renaming.
Keystore — your signing key is not tied to the package name, but the Play listing is. Keep the keystore, change the identifier.

One command instead of ten

BowlerKit automates all of this: the rename-package guide covers the CLI command that updates the package name, bundle identifier, deep-link scheme, and Firebase config across the whole project consistently. See the quick start to generate a project with the right identifiers from minute one.