A practical walkthrough for using a0.dev to generate a React Native and Expo app, preview it on your iPhone, and set it up for iOS — from writing your first prompt to understanding the path toward the App Store.
This guide walks through building your first iOS app with a0.dev. The goal is a running React Native and Expo app previewed on a real iPhone.
Before you begin, set expectations. a0.dev generates cross-platform React Native code, not native Swift, so everything here follows the Expo workflow.
You will want a few things ready: an a0.dev account, an iPhone for on-device preview, and ideally a Mac if you plan to do local builds later.
A working knowledge of JavaScript or TypeScript helps when you start editing generated code. Also plan ahead for release: shipping to the App Store eventually requires an Apple Developer Program membership, though you do not need it just to prototype.
Everything starts with your prompt. The quality of the generated app tracks closely with how specific and structured your description is.
Instead of a vague sentence, describe the app's purpose, its main screens, and the key user flow. For example, name the tabs, the primary list, and the main action a user takes.
A useful pattern is to describe it like a brief: what the app does, who uses it, the three or four core screens, and the visual style. Concrete detail produces better first drafts.
Avoid trying to describe the entire app in one giant prompt. Start with the core, get a working shell, then iterate — that approach consistently produces cleaner results.
Once you submit the prompt, a0.dev generates the React Native project and gives you a way to preview it. The on-device preview is the fastest way to validate the result.
Typically this uses an Expo runtime, meaning you view the app through Expo on your phone rather than installing a full native build. Follow a0.dev's in-product instructions to open the preview on your device.
Interact with the app immediately. Tap through the navigation, check the screens, and note what matches your intent and what does not.
This tight loop — prompt, preview, evaluate — is the whole point of the tool. Use it aggressively before writing any code by hand.
Your first generation is a draft. Refine it by prompting for specific changes rather than regenerating from scratch.
Ask for concrete adjustments: change a screen's layout, add a new tab, adjust colors, or wire a button to a new screen. Small, focused requests produce more predictable edits.
Work one concern at a time. If you bundle five unrelated changes into one prompt, it becomes harder to tell what changed and to roll back if something breaks.
Re-preview after each meaningful change. Treat the preview as your source of truth for whether the app behaves the way you described.
Once the app looks right, look under the hood. a0.dev produces standard React Native and Expo code, which you should read before relying on it.
Check how navigation is structured, how state is managed, and whether data is real or placeholder. Generated apps often use mock data that you will need to replace with real API calls.
Look for gaps typical of AI output: missing error handling, loading states that are not wired up, and hardcoded values that belong in configuration.
This review step is where your engineering judgment matters most. The AI gives you a foundation; making it robust is your job.
For an iOS app, some configuration is non-negotiable. In an Expo project this lives primarily in the app config (app.json or app.config.js).
Set the iOS bundle identifier — a unique reverse-DNS string like com.yourcompany.yourapp. This identifier ties your app to your Apple Developer account and App Store record.
Configure the app name, icon, and splash screen. Expo has clear conventions for asset sizes and placement, so follow its documentation to avoid rejected builds later.
If your app uses device capabilities like the camera, location, or notifications, declare the required iOS permission usage descriptions. Apple rejects apps that access these without proper purpose strings.
A prototype becomes a product when it does real work. This usually means replacing placeholder data and connecting to backend services.
Wire your screens to real APIs. Because the output is standard React Native, you use ordinary fetch or a library like Axios, and you can adopt data-fetching patterns you already know.
Add authentication, storage, or push notifications as needed. Expo offers documented modules for many of these, which integrate cleanly with a0.dev's Expo-based output.
Test each addition on your device. Real functionality introduces real failure modes — network errors, empty states, permission denials — that a static preview never exercises.
When the app is ready, releasing to iOS follows the standard Expo and EAS route. This is the same path any Expo app takes.
You will use EAS Build to compile a native iOS binary in the cloud, or locally with a Mac. EAS handles signing and provisioning when configured with your Apple credentials.
You then submit the build to App Store Connect, complete your app's metadata and privacy details, and send it for App Review. An Apple Developer Program membership is required for this entire stage.
Budget time for review. Apple can request changes, and first submissions often surface issues with privacy strings, incomplete features, or metadata that you will fix and resubmit.
Keep prompts specific and iterative. The single biggest lever on output quality is how clearly you describe what you want, one focused change at a time.
Do not skip the code review. AI-generated apps are drafts; treating them as production-ready is the most common mistake newcomers make.
Learn the Expo basics early. Understanding app config, EAS Build, and the Expo runtime pays off the moment you move beyond preview toward a real release.
Finally, verify anything cost- or feature-related against official sources. a0.dev, Expo, and Apple all publish current documentation and pricing, and those are the authoritative references.
Not every generation lands cleanly, and that is normal. When a screen looks wrong or a flow does not behave as intended, resist the urge to start over from a blank prompt.
Instead, describe the specific gap between what you see and what you wanted. Point at the exact screen and the exact behavior, and ask for that one change.
If a layout is stubborn, it is often faster to accept the generated structure and adjust it in code than to keep re-prompting. Standard React Native styling gives you full control at that point.
Keep a simple record of what you changed and why. A short changelog helps you retrace your steps when a later prompt undoes an earlier fix, which happens with iterative generation.
Not necessarily for prototyping or cloud builds. EAS Build can compile iOS apps in the cloud. However, a Mac with Xcode is valuable for local builds, simulators, and debugging, and some workflows are smoother with one.
Specific but focused. Describe the app's purpose, the main screens, the core user flow, and the visual style. Start with the core app rather than every feature at once, then iterate with follow-up prompts.
No. The on-device preview typically runs through an Expo runtime for fast iteration. A real App Store build is a compiled native binary produced by EAS Build, which you submit through App Store Connect.
Yes. a0.dev produces standard React Native and Expo code, which you can and should review and extend. Replacing placeholder data with real APIs and adding error handling are common next steps.
An Apple Developer Program membership, a compiled build via EAS, completed metadata and privacy details in App Store Connect, and a successful App Review. The AI builds the app but does not remove these requirements.