How to build an Android app: Android Studio, Kotlin and AI agents

What are your options for building an Android app?

Android’s development tools run on almost any computer, which makes it the easier of the two big phone platforms to start on if you do not own a Mac. There are still three real paths, and the right one depends on whether you want Android only or both stores.

Android Studio’s own page says it can be installed on Windows, macOS, Linux and ChromeOS, which is the main practical difference from iPhone development, where the native toolchain needs a Mac. The iPhone guide covers that side, and how to make an app compares writing code yourself, directing an AI agent and using a builder.

What does Android Studio give you?

Android Studio is the official IDE for Android development. Google’s introduction lists a Gradle-based build system, an emulator, Live Edit for updating composables on an emulator or a real device, lint tools and testing frameworks. You do not have to assemble any of that yourself.

A new project follows a fixed layout, and knowing it makes an AI agent’s changes easier to read. In the Android view, each app module has three parts, per Google’s Android Studio introduction:

• manifests holds AndroidManifest.xml, where the app declares its permissions and screens.
• kotlin+java holds the source code and the unit tests.
• res holds strings, images and other non-code resources.
• Gradle Scripts holds the build files. These control the app’s version, its target API level and its dependencies.

For the interface, Google describes Jetpack Compose as the modern toolkit for building Android UI. New projects in Android Studio can start from a Compose template, so choose it unless you are maintaining older code.

How do you build your first Android app, step by step?

1. Install Android Studio. Download it from the Android Studio page and follow the setup wizard. It installs the Android SDK for you.
2. Create the project. Choose a new project with a Compose-based Activity template. Run it before you change anything, to prove the toolchain works. Google’s Hello World codelab walks through this.
3. Run it on the emulator. Create a virtual device in Device Manager and press Run. The emulator guide explains how it works.
4. Write the brief. One user, one job, the screens in order, what is out of scope. The template below gives you the shape.
5. Build one screen at a time. Ask your agent for a plan first, then one screen, then run it. Read every diff. An agent can add permissions or libraries you did not ask for, and the manifest and Gradle files are where that shows up.
6. Run it on your own phone. Google’s guide to running on a device says to open Settings, go to Developer options and enable USB debugging. If Developer options is missing, the same page explains how to turn it on.
7. Fix what real use breaks. Permission prompts, slow connections, small screens and the back button all behave differently on a real handset.

Build a first version of an Android app called [name] in Kotlin with Jetpack Compose, in the Android Studio project that is already open.

User: [one specific person and when they need this].
Problem: [what they do today and why it fails].
Success: [the one thing the user can do].

Screens, in order:
1. [Main screen: what it shows]
2. [Input screen: what the user enters or captures]
3. [Result screen: what comes back]

Data: [what is stored]. Keep everything on the device; no accounts, no servers.
Permissions: only [camera / location / notifications / none]. Request each at the moment it is needed and handle the user saying no.
Out of scope: sign-in, payments, widgets, tablet layouts, ads.
Edge cases: no network, permission denied, empty result, rotating the phone.

Rules:
- Do not add a library without telling me why.
- Do not change the target API level or add permissions I did not list.
- Before writing code, list the files and composables you will create and wait for my go-ahead.
- After each step, tell me how to run it and what I should see on the emulator.

The AI coding agent guide explains the working method in detail, and the free AI Coding Prompt Builder will draft the brief from your answers.

What should you tell a coding agent about your Android project?

Terminal agents such as Claude Code read a project instruction file at the start of every session. For an Android project, the useful content is the commands that build and test it, plus the rules you do not want broken. Put this in a CLAUDE.md at the project root and adjust it.

# [App name]

Android app in Kotlin with Jetpack Compose. Single module, no backend.

## Commands
- Build a debug APK: ./gradlew assembleDebug
- Install on the connected device or emulator: ./gradlew installDebug
- Run unit tests: ./gradlew test
- Build the release bundle for Google Play: ./gradlew bundleRelease

## Rules
- Do not change applicationId, minSdk or targetSdk without asking.
- Do not add permissions to AndroidManifest.xml without asking.
- Do not add a dependency without saying why and what it costs in app size.
- Never commit keystores, keystore passwords or API keys. Read secrets from local.properties or environment variables.
- All user-facing text goes in res/values/strings.xml, not in code.

## Definition of done for a change
- It builds with assembleDebug.
- Tests pass.
- You told me how to see the change on the emulator.

The release bundle line matters because of how Google Play works. Google’s app bundle documentation says that since August 2021 new apps are required to publish with the Android App Bundle, so the file you send to the store is an .aab, not an .apk.

Should you use Flutter, React Native or a no-code tool instead?

If the app must exist on both Android and iPhone, a cross-platform framework saves you from writing it twice. Flutter is Google’s framework, and its setup page is the place to start. React Native with Expo suits you if you already know JavaScript or TypeScript; Expo’s setup page describes Expo Go for learning and development builds for your own app.

The trade is distance from the platform. Anything that touches an unusual phone feature should be checked against the framework’s documentation before you commit to it. For a first app with one job, native Kotlin with an AI agent and a cross-platform framework are close in effort, so choose by where your users are.

No-code builders also publish Android apps. The no-code guide lists what to check first, such as whether you can export your code and what a paid plan adds.

What must you know before releasing on Google Play?

Getting an app onto Google Play is a separate job from building it, and it has its own rules. The full process is in the Google Play publishing guide. Three points matter while you are still building, because they are cheaper to handle early:

• Target API level. Google’s target API level page says that from August 31, 2026, new apps and app updates must target Android 16 (API level 36) or higher, with different minimums for Wear OS, Android Automotive OS, Android TV and Android XR. Create your project with a current Android Studio and you start in the right place.
• Signing. Android’s app signing documentation says you sign the app bundle with an upload key before uploading it to Play Console and that Play App Signing handles the rest. Keep the keystore and its passwords out of version control.
• Testing requirement for new personal accounts. A personal developer account created after November 13, 2023 must run a closed test with at least 12 testers opted in for 14 days before it can publish publicly. Start recruiting testers early, since this is the step that adds calendar time.

How much does an Android app cost and how long does it take?

Cash cost for a self-built app is small: the USD 25 one-off Google Play registration fee, plus whatever AI tools, hosting or backend you choose. Hiring is a different order of magnitude, since cost is hours times an hourly rate. The cost page shows the arithmetic and how long an app takes gives a calendar. Add at least two weeks for the closed test if you use a personal account.

If you want a project but have no idea yet, the board has plenty. Browse the ideas; each one has a generated build prompt you can paste into Claude Code, Cursor or Lovable. Prefer a mobile-first one with a single job, such as an idea that needs only the camera or a list. And if you have an idea you will never build, post it. It is free and needs no account.