Pre-publish health check

Why run a pre-publish health check?

Before you commit to a production build or submit your mobile app to the App Store or Google Play, it's critical to verify that the app behaves as expected on real devices. A pre-publish health check catches UI glitches, navigation issues, API errors, and performance problems before they reach your users - saving you time and embarrassment.

Emergent generates a live preview URL for every mobile app. Use it to test thoroughly before you trigger a production build or start the publishing to the stores process.

Preview & test the mobile app first

Test early, test often

Your workspace provides an instant preview of the mobile app. Open it on your phone to check layout, navigation, and features - all without waiting for a compile.

Every time the AI agents rebuild your mobile app, Emergent updates the preview. You can:

Open the preview URL in your browser (desktop or mobile) to see a web-based simulation.
Scan the QR code with your phone to launch the live app in Expo Go (see below).
Navigate through every screen, tap buttons, fill forms, and verify API calls.

What to check:

UI renders correctly on both iOS and Android (test on at least one device from each platform if possible).
Navigation flows work end-to-end (tab bars, drawer menus, deep links).
Forms validate input and display error messages.
Images, fonts, and icons load.
API calls succeed (check network panel or logs if something breaks).
Authentication flows and third-party SDKs behave as expected. (Push notifications can't be tested in preview - generate a build and test on a physical device.)

If you spot a bug, describe it in chat - Emergent's agents will fix the code and regenerate the preview. Repeat until the app is solid.

Local testing & testing on your phone with Expo Go

The fastest way to test your mobile app on a real device is with Expo Go, a free companion app that runs Expo projects instantly - no Xcode, no Android Studio, no builds.

Install Expo Go on your phone

Download Expo Go from the App Store (iOS) or Google Play (Android). It's free and maintained by Expo.

Open the preview in your workspace

In the Emergent workspace, locate the mobile app preview panel. You'll see a QR code and a preview URL. See a tour of the workspace if you need help finding it.

Scan the QR code

iOS: Open Expo Go and scan the QR code from inside the app. Newer projects use device-code auth instead of a QR code.
Android: Open Expo Go and tap Scan QR Code, then point your camera at the code.

The app will load and run directly on your device, connected to Emergent's live preview server.

Iterate and re-test

Make changes in chat, wait for the agents to rebuild, and the app in Expo Go will hot-reload automatically - usually within seconds. You can iterate quickly without leaving your phone.

Use Expo Go for all pre-publish testing

Expo Go gives you a production-like experience on real hardware. Test gestures, animations, keyboard behavior, and camera/location permissions. Only move to a full production build once the app is stable.

Expo Go limitations

Expo Go cannot run apps with custom native code (e.g., certain third-party SDKs or native modules outside the Expo SDK). If your app uses such features, you'll need a development build or a production build. Most Emergent apps work fine in Expo Go.

Build plans & requirements

When you're ready to generate a production build - either for local testing, TestFlight/internal testing, or store submission - you trigger a native build from the Publish panel. Emergent manages the Expo/EAS account on your behalf; you never need to create an Expo account, install eas-cli, purchase EAS credits, or edit eas.json.

Paid Emergent plan required

Native builds (APK/AAB/IPA) require a paid Emergent plan (Standard or above). The gate is your Emergent subscription, not Expo credits. See plans & the free tier for how Emergent's own pricing works.

How builds are triggered in Emergent

When you trigger a native build from the Publish panel, the platform:

Builds from your last published code (fix any issues → re-publish via Re-publish → then trigger the build, this is the most common gotcha).
Runs the EAS build process using Emergent's managed Expo account.
Queues the build on Expo's servers.
Returns the build artifacts once complete. Android: an APK and an AAB - the AAB is what you upload to the Google Play Console, and the APK can't be tested on a local device without Expo Go. iOS: no IPA is provided - Emergent uploads the build directly to your TestFlight.

See Start with your idea for step-by-step instructions.