# React Native mobile app developer: why start with Expo

> To start as a React Native mobile app developer, Expo is a simple starting point. You write your app in JavaScript or TypeScript, watch it run on your iPhone while you code, and don't have to handle all the native setup on day one. It's the tech foundation of my apps, and of the iOS Kit's starter code.

Original page: [React Native mobile app: getting started with Expo](https://devoria.fr/en/expertise/react-native-expo-mobile-app)
Author: [Mehdi Azizi](https://devoria.fr/en/mehdi-azizi)
Last reviewed: 2026-10-09

## What you'll learn

### One language to learn

JavaScript or TypeScript, the language of the web. AIs know it well, which makes them useful for helping you write and fix your code.

### Your app on your iPhone while you code

Every change shows up on your phone. You learn by seeing results, not by reading theory.

### Builds made in the cloud

Expo's services compile your app and send it to TestFlight, saving you most of the native setup.

### Ready-made building blocks

Notifications, purchases, camera, storage: the common modules already exist. You assemble them instead of rewriting them.

### Limits you can spot

Some features need native code. You learn to spot them before committing, so you pick an idea within reach.

## Step by step

1. You install Expo, create your project and run your first screen on your iPhone.
2. You build the core feature and send a build to TestFlight.
3. You add RevenueCat and PostHog, two modules that plug into an Expo project.
4. You prepare the final build and send it to Apple.

## Why learn with me

My apps, Solys, TradaZen, Nolera, and Vigie, are built with Expo. I also know where Expo stops: the Solys alarm uses AlarmKit, natively, because an alarm that breaks through silent mode requires it. You learn with the tool I use every day, limits included.

[TradaZen case study](https://devoria.fr/en/blog/tradazen-case-study-launching-iphone-app): timeline, rejections and launch.

## FAQ

### React Native or Swift to start?

Swift is Apple's native language and it has its strengths. For a first app with a subscription, React Native with Expo gives you more ready-made pieces and a language AIs handle well.

### Is Expo only for small apps?

No. Published apps run on Expo, and when a feature needs native code, you add a module without rewriting everything.

### Can I make an Android version too?

Expo allows it, and the kit's code compiles for Android, but all the polish is done for iPhone and the App Store. One well-published first app beats a half-finished app on two platforms.

## Free guides

- [Publish an iOS App Without a Mac: Expo and EAS Guide](https://devoria.fr/en/blog/publish-ios-app-without-mac-expo-eas)
- [iOS or Android App: Which Should You Build First?](https://devoria.fr/en/blog/ios-or-android-app-which-first)
- [TestFlight: Test Your iPhone App Before Submitting](https://devoria.fr/en/blog/testflight-test-iphone-app-before-submitting)
- [Secret API key in an Expo app: what to protect](https://devoria.fr/en/blog/secret-api-key-expo-app-what-to-protect)
- [Build an App with Codex: A Beginner's Guide](https://devoria.fr/en/blog/build-an-app-with-codex-beginners-guide)

## The kit for this step

[iOS Kit](https://devoria.fr/en/kits/ios): Build your iPhone app with Claude Code: the starter code behind my apps, skills that check its work, and the Apple Review, Screenshots and ASO kits. 129,99 €.