Tutorial: Build an app with an AI agent

An introduction to a tutorial on building an Expo app that runs on Android, iOS, and the web by directing an AI coding agent, with no programming experience required.

For the complete documentation index, see llms.txt. Use this file to discover all available pages.

In this tutorial, you'll build a complete app for Android, iOS, and the web without writing code yourself. Instead, you'll direct an AI coding agent, such as Claude Code, Codex, or Cursor, and check the results live on your own phone after every step.

This tutorial is for builders: people who have an idea for an app but don't have a programming background. If you'd rather learn to write the code yourself, follow the Expo tutorial instead. It builds the same app, one code snippet at a time.

What you'll build

You'll build StickerSmash, an app that lets you pick a photo, place an emoji sticker on it, move and resize the sticker with your fingers, and save the result to your photo library:

How this tutorial works

Every chapter follows the same loop:

1. Prompt: paste a suggested prompt into your AI agent.
2. Build: the agent writes the code and the app updates on your phone within seconds.
3. Verify: check that the app does what you asked, right on your phone.
4. Re-prompt: if something looks off, tell the agent what you see and let it fix the problem.

You are the product owner and the tester. The agent is the programmer.

AI agents don't produce identical results every time, so your app won't match our screenshots pixel for pixel. That's expected. The prompts describe the outcome you want, and the screenshots show approximately what you should see. Feel free to edit the prompts to match your own taste: pick different colors, change the wording on buttons, make it yours.

What you'll need

• A computer running macOS, Windows, or Linux.
• An Android or iOS phone.
• About an hour. The first chapter walks you through installing every tool from scratch, so you don't need anything set up in advance.

Chapters

1. Set up your tools
2. Create your first app
3. Build the home screen
4. Add stickers
5. Save your creation
6. Finishing touches

Next step