Build a mobile app with AI.

To build a mobile app with AI in 2026, pick one of three paths. Use a cross-platform framework such as Expo or Flutter with a coding agent, write native code with the agents now built into Xcode and Android Studio, or start in an app builder that exports real code. Then budget for the stores. Apple charges 99 USD a year and Google Play 25 USD once, and both have rules that catch first-time developers.

AI now writes most of the screens, forms and plumbing. What it still gets wrong is the mobile-specific part: versions, permissions, signing and store paperwork. This guide covers each path, the accounts and 2026 rules we checked on Apple’s and Google’s own pages, and how to test on real phones.

01Three ways to build a mobile app with AI

For most first apps, cross-platform wins. You write one app, test it on both platforms, and any coding agent can work on it. Go native when the app is mostly camera, sensors, background work or platform features such as widgets.

Native got easier in 2026. In February, Apple’s Xcode 26.3 added agentic coding with Anthropic’s Claude Agent and OpenAI’s Codex. Xcode 27, out since September, still supports both. The agents can search documentation, change project settings, and check their work by capturing Xcode Previews. Android Studio’s Agent Mode plans multi-step tasks, builds the project and fixes errors. It can also run the app on a connected device, take screenshots and read the logs.

App builders sit at the easy end. FlutterFlow, for example, builds Flutter apps visually, exports the code and deploys to both stores. If you have never built an app, our guide to building an app without coding compares the builders.

02Your first fifteen minutes with Expo

Expo is a framework and toolset for React Native apps. These three commands create a starter app and serve it to your phone:

npx create-expo-app@latest my-app
cd my-app
npx expo start

Scan the QR code with your phone while it is on the same Wi-Fi network, and the app opens in the Expo Go app. On an iPhone, Expo’s docs say Expo Go and your computer must be signed in to the same Expo account, so run npx expo login first. On a Mac with Xcode, press i to open the iOS Simulator instead.

We ran these commands on September 23, 2026. They installed Expo SDK 57 with React Native 0.86, bundled the app for iOS and Android, and opened it in Expo Go on an iOS 26.2 simulator.

One quirk we hit: on the fresh project, npx tsc --noEmit reported two errors about stylesheet types. They disappeared after the first npx expo start, which generates an expo-env.d.ts file. If an agent starts writing type declarations to fix errors like these, stop it and run the dev server first.

03How much do developer accounts cost?

You can build and test for free. You pay when you want other people to install the app from a store.

Before you pay Apple, you can already run your app on your own iPhone through Xcode with a free account. That setup is limited to three devices, and the app stops working after seven days until you reinstall it. TestFlight, Apple’s beta testing service, needs the paid membership.

Google asks personal accounts created after November 13, 2023 to run a closed test before production access. At least 12 testers must stay opted in for at least 14 days in a row. Line up your testers before launch week, not during it.

04The 2026 store rules that catch first-time developers

Design around these rules from day one.

The account rule shapes your backend, so decide early how login and deletion will work. Our guides to adding login safely and choosing a database cover both halves.

Developer verification applies beyond Google Play. If you distribute on Play, you verify in Play Console. If you only distribute elsewhere, Google’s new Android Developer Console handles it. Students and hobbyists can use a free limited distribution account to share apps with up to 20 devices.

05What AI does well, and badly, in mobile work

AI is strong where mobile work looks like web work, and weak where the platform has its own rules. So give it the rules: the versioned docs, your SDK version, and a plain reason for every permission it adds.

This is an Expo SDK 57 app. Read package.json and the versioned Expo docs before you write code. Do not rely on memory for Expo or React Native APIs.
Add [feature]. Install packages only with npx expo install.
For every permission the feature needs, write the text the user will see and explain why we need it.
Handle these cases: permission denied, no network, and a slow response.
When you are done, run the linter and the typecheck, and show me the output.

Never put a secret key in a mobile app. Anyone can unpack an app and read it, so calls to paid APIs belong on your server.

06Test on real devices before you submit

A simulator is fast for daily work, but it runs on your Mac’s processor and network. Real phones reveal what simulators hide: slow startup on older hardware, a keyboard covering a button, a permission prompt that appears at the wrong moment.

1. 01

   Run it on your own phone early

   Use Expo Go or a development build for cross-platform apps. For native iPhone apps, a free Apple account lets you install from Xcode. On Android, turn on USB debugging and let Android Studio deploy.

2. 02

   Borrow an old, small phone

   Test on the oldest and smallest device you can find. Text that fits a new large phone often wraps or overflows there.

3. 03

   Break it on purpose

   Turn on airplane mode mid-task, deny every permission, switch to dark mode and the largest text size, and take a phone call while the app is open.

4. 04

   Recruit real testers

   Use TestFlight for iPhone and a closed test track for Android. On a new personal Play account, the closed test is required anyway.

5. 05

   Let the agent watch too

   Android Studio’s agent can run the app on a connected device, take screenshots and read the logs. Xcode’s agents can check their work with previews. Treat what they report as a first pass, not a sign-off.

07FAQ

Next, keep your app’s secrets off the device with our guide to API key safety, plan the business side with building a SaaS with AI, or see the same idea come together as a Chrome extension in under an hour.