Native Mobile Apps

Learn how to build a native mobile app with Agent, test it on your phone, and submit to App Review for App Store publishing.

Build iOS and Android apps with Agent, preview them on your phone, and prepare builds through a guided flow.

To build or preview a native iOS app, use the Project Editor at replit.com. Native mobile app work is also available in the Replit Android app where supported.

Getting started

You can get to a working mobile app in a few steps:

1. Create a mobile app

   On the Replit home screen, describe your app idea and select Mobile app as the app type.

   
2. Test your app

   You have two ways to preview a mobile app while you build:

   • In the Project Editor: In the Preview panel’s device selector, choose iOS Simulator or Android Emulator. A real simulator streams into the Project Editor so you can tap around without leaving Replit. No Xcode or Android Studio required.
   • On a real phone with Expo Go: Install Expo Go on your iPhone or Android device. In the Project Editor, select Open in Expo Go in the Preview panel and scan the QR code.

   
3. Iterate with Agent

   Ask Agent to add features, connect data sources, or integrate services. Keep testing in the simulator or on your phone as you iterate.

The Project Editor’s iOS Simulator and Android Emulator show the native version of your app, including platform-specific styling and most native components. For features that rely on real hardware — haptics, the camera, push notifications, or location — test on a real phone with Expo Go.

Preview on a simulator or emulator

Replit allows you to run and test your mobile apps on your phone using Expo. Alternatively, Replit streams a real iOS Simulator or Android Emulator right into the Preview panel. Changes you make with Agent hot-reload in the simulator, just as they do on a real device.

iOS Simulator and Android Emulator previews are available to builders on Core, Pro, and Enterprise plans. Mobile apps only — the option is hidden for web-only projects.

How to open a simulator

1. Open your mobile project

   Open a project that has a mobile artifact.

2. Pick your device

   In the Preview panel’s device selector at the top, choose iOS Simulator or Android Emulator. The simulator boots in place of the web preview.

3. Interact like a real device

   Tap, swipe, type, and navigate using your mouse and keyboard. Select Restart in the toolbar to reload the app without restarting the simulator.

The simulator runs in the cloud and streams to your browser, so there’s nothing to download and nothing to set up. Your project’s files stay on Replit.

Browser support

• Chrome, Safari, and Chromium-based browsers are fully supported.
• Firefox is not supported. The iOS and Android options appear disabled with a “Firefox not supported” note when you open Replit in Firefox. This is a limitation of the streaming technology that powers the simulator.

When to use Expo Go instead

Use Expo Go on a real phone when you need to test features that rely on real hardware or when you want to share a preview with someone who isn’t at your computer:

• Camera, microphone, haptics, or other native sensors
• Push notifications
• Real-world GPS location
• Sharing a development preview with a teammate, tester, or investor

To open your app in Expo Go, open the project on replit.com, select Open in Expo Go in the Project Editor’s Preview panel, and scan the QR code with the Expo Go app on your phone.

Fullscreen simulator

From a mobile artifact card, select More actions → Open in iOS Simulator or Open in Android Emulator to open the simulator in its own tab for a larger viewport.

Why build a mobile app?

Build a mobile app when you want:

• A native experience: Fast performance, smooth interactions, and platform-native UI.
• Device capabilities: Camera, push notifications, location, and more.
• App Store distribution: A shareable listing that people can discover and install after Apple’s App Review process.

Key features

• AI-first creation: Describe your app, and Agent scaffolds a working mobile app.
• Project Editor preview: Test on an iOS Simulator or Android Emulator without leaving Replit, or preview on your phone with Expo Go.
• Full-stack by default: Add server routes, a Database, App Storage, Connectors, and AI integrations as your app grows.
• Guided submission: Prepare builds for TestFlight and App Store submission without managing local iOS toolchains.

Development workflow

There are three stages for accessing your app, each with different audiences and capabilities:

Stage	Who can access	How to access	Best for
Development	You	Project Editor simulator, or QR code for Expo Go	Building and iterating
Deploy	Testers with Expo Go	Public URL with QR code	Development previews, prototyping, and demos
App Store	Anyone	Download from App Store after App Review	Production release

Development: When you start your app, you can preview it in the Project Editor’s iOS Simulator or Android Emulator, or scan a QR code from the Preview panel to open it in Expo Go on your phone.

Deploy: When you click Publish, Replit creates a public URL with a QR code for Expo Go. This is ideal for development previews and prototyping—show investors, gather feedback, or test with friends before committing to the App Store process.

App Store: When you submit to the App Store, Apple reviews your app. After approval, people can download and install it from the App Store. This requires an Apple Developer account.

Publishing overview

When you prepare an iOS release, the flow typically goes:

• Publish from the Project Editor
• Submit a build to TestFlight
• Promote a TestFlight build to the App Store in App Store Connect

To submit builds to TestFlight and the App Store, Apple requires an Apple Developer Program membership.

For a complete walkthrough, see the Build and launch a mobile app tutorial.

Where to build native mobile apps

Your Replit environment runs in the cloud, not on your local machine. To build a native mobile app, use the Project Editor at replit.com. The mobile app workflow—Agent scaffolding, Expo Go previews, simulator and emulator testing, TestFlight builds, and App Store submission—runs in the Project Editor.

Native mobile app work is also available in the Replit Android app where supported. If you’re using the Replit iOS app, open the project on replit.com to create, preview, build, or submit native mobile apps.

How the technology works

Your mobile app is built with a stack of technologies that work together. This section explains what powers your app and how the pieces fit together.

The technology stack

• React Native is an open-source framework that lets you write one codebase and compile it to iOS, Android, and web. It renders platform-native UI components, not a webview.
• Expo simplifies React Native development by handling builds, managing native modules, and providing tools like Expo Go for previews.
• Expo Go is a free app you install on your phone. It runs your development preview so you can test on a real device without building a full native binary.

When you run your app, the Metro bundler compiles your code and pushes it to your device. The first build takes longer because there’s no cache. Subsequent builds are faster.

Architecture: server and client

When you prepare a mobile app for preview or distribution, you’re working with two things:

1. A server that runs on Replit in the cloud. This handles your database, API routes, AI integrations, and backend logic.
2. A client app that runs on a person’s phone. This is the native app previewed in Expo Go during development or distributed through app stores after review.

This separation gives you flexibility. You can run complex logic on the server (where you have access to Replit’s Database, Object Storage, and Connectors) and keep the client lightweight. As you build, think about what should happen on the phone versus what should happen in the cloud.

Considerations

• Publishing requirements: Apple sets the requirements for TestFlight and the App Store, and Apple reviews iOS apps before distribution.
• Android publishing: You can build cross-platform apps for iOS and Android. Publishing to Google Play is not supported through a guided experience yet, but can be accomplished manually.
• Native changes: Changes like app icons or permissions usually require a new store build.

Troubleshooting

If you run into issues while developing your mobile app, see Mobile app troubleshooting for common problems and solutions.

Next steps

• Learn how Agent works: Agent
• Explore integrations: Integrations
• Use Replit on mobile: Replit Mobile App
• Read more about Expo: Expo
• Manage TestFlight and submissions: App Store Connect

FAQs

What is Expo?

Expo is what Agent uses to build your mobile app on Replit. It is an open-source platform and toolchain for building, running, and deploying cross-platform native apps with React Native. Learn more at https://expo.dev.

What is React Native?

React Native is an open-source framework from Meta for building native iOS and Android apps using React and JavaScript or TypeScript. It renders platform-native UI components (not a webview), so your app looks and feels native.

What is Expo Go?

Expo Go is a free app you install on your phone from the App Store or Google Play. It lets you preview your mobile app during development without building a full native binary. When you scan the QR code in the Project Editor, Expo Go downloads and runs your app code.

What's the difference between Expo Go and a dev build?

Expo Go is a pre-built app that runs your code. It’s fast to set up but only supports modules included in the Expo SDK.

Dev builds are custom native binaries that can include any native module. They require more setup (EAS Build or local Xcode/Android Studio) but offer more flexibility.

Replit uses Expo Go for development previews. If you need native modules not supported in Expo Go, you may need to explore dev builds through Expo’s documentation.

How is this different from a mobile-responsive web app?

A mobile-responsive web app is a website that adapts its layout in the browser. A React Native app is a native application installed on the device that uses platform APIs (camera, haptics, push notifications), offers better access to hardware and offline capabilities, and is distributed via app stores. Responsive web can be great for reach and zero-install; native is best when you need device features, performance, or App Store distribution.

Do I need a Mac or Xcode?

No. Replit and Expo manage the build process for you in the cloud.

Can I preview without an Apple Developer account?

Yes. You can preview in the Project Editor’s iOS Simulator or with Expo Go on your phone. You only need an Apple Developer account when you’re ready to submit to TestFlight or the App Store.

Is Android supported?

Yes. You can build cross-platform apps for iOS and Android from the same codebase. Preview on an Android Emulator in the Project Editor or on an Android device with Expo Go. Publishing to Google Play can be done manually.

What about servers and databases?

Use Replit’s built-in PostgreSQL, Object Storage, Connectors, and AI integrations—no separate infrastructure required. Your server runs on Replit and your mobile app connects to it.

Should I test in the Project Editor simulator or on a real phone?

Use both at different times. The iOS Simulator and Android Emulator in the Project Editor show the native version of your app and cover most day-to-day testing — layout, navigation, native components, and platform styling. Switch to a real phone with Expo Go when you need to test features that depend on real hardware, like the camera, haptics, push notifications, or GPS location.