Build an app for a school project or hackathon without coding

You can build a working app for a school project or a hackathon without coding: pick one small idea, describe it in a single prompt to App Builder Agent, and the AI agent writes a React Native app that you show in a live phone preview and install on an Android phone as an APK. The free plan (500K AI tokens a month at the time of writing) is enough for a first version and a live demo in the preview; a free APK download puts it on a phone. In your presentation, say plainly that an AI agent wrote the code from your description and that you tested and changed it.

A school project or a hackathon gives you a few days, sometimes a few hours, and a room full of people who will judge the result on whether it works. That is exactly the situation an AI app builder is good at: you spend your time on the idea and the demo, not on setting up a development environment. This guide walks through picking an idea that fits the time, the one prompt to paste, how to demo it, and how to describe the build process honestly.

Pick an idea that fits the time you have

The projects that fail at hackathons are not the boring ones; they are the ones that tried to do six things. Pick one problem and one main screen. Good student projects share a shape: a clear user (students in your class, people at the school library, visitors to a science fair), one thing they do (answer questions, log something, look something up), and a result they can see (a score, a chart, a list).

• Quiz or revision app for one subject, with a result screen and a retry mode. The most reliable choice; see the quiz app guide for what to ask for.
• Timetable and homework app for your own class, with reminders. The timetable and homework guide has a prompt you can adapt.
• Campus or event helper: a map of rooms, a schedule of talks, a lost-and-found list.
• Data project: log something (water intake, noise levels in the library, bus delays) and show a chart.
• Accessibility helper: a large-text reader, a colour-contrast checker, an exam timer with visual cues.

Write the idea as one sentence before you open the builder: "An app where students in my chemistry class practise 60 exam questions by topic and see which topics they get wrong." If you cannot write that sentence, the idea is not scoped yet.

What the app needs

Keep the list short. Three or four screens is plenty for a demo, and every extra feature is another thing that can break on stage.

• A home screen that says what the app is and offers one clear action.
• The main screen where the thing happens: the quiz, the log form, the schedule.
• A result or summary screen: score, chart, streak, list of missed items. Judges like to see an outcome.
• Data that ships inside the app so it works without Wi-Fi in the presentation room. Put your questions, rooms or events in one plain list the agent can read.
• Storage on the device for progress, so you can show that the app remembers something between launches.
• An About screen with the team names and one paragraph on how it was built. It takes one line to ask for and it answers the question every judge asks.

Skip accounts, login and a backend unless the project is specifically about them. A hosted backend is available when you need shared data (for example a class leaderboard), but it adds things to explain and one more place to fail during a demo.

The prompt to paste

Open App Builder Agent, sign in with a Google account, choose a mobile app, and paste one message that names the audience, the content and the screens. This example is for a revision app; swap the subject and the numbers.

Two habits make the rest of the build easier. First, ask for one change per message once the first version is up. Second, when something looks wrong, describe what you see and what you expected ("the Results screen shows 0/15 even though I answered 12 correctly") instead of guessing at the cause.

What you get in the first minutes

The agent writes the screens, wires up navigation and mounts the app in a phone preview in the browser. Tap through it the way a judge would: pick a topic, answer wrong on purpose, check that the Results screen lists what you missed, close and reopen to confirm History survived. The generated React Native code is visible in the editor next to the preview; you do not have to read it, but it is worth opening once so you can point to it later.

Then iterate by describing changes. Typical follow-ups for a student project:

If you have questions in a spreadsheet, paste twenty rows and say "use this format for the question bank"; the agent will match the columns. Stop adding features about an hour before the deadline and spend that hour testing on a real phone.

Presenting it: live preview and a phone

You have two ways to show the app, and the strongest presentations use both.

1. The live preview on the projector. Open the builder on the presentation laptop and show the phone preview full screen. The audience sees the app running and, if asked, you can switch to the code tab. You can even make a small change live ("change the accent colour to the school green") to show how the build process works.
2. An APK on a real phone. Click Download APK in the preview header to get an installable Android build. Install it on your own phone (Android asks you to allow installs from the browser or file manager) and hand it to a judge. An app running on a phone in someone's hand is far more convincing than a screen recording. If the install fails, the App not installed troubleshooting guide covers the usual causes.

Builds are Android only. If your team only has iPhones, demo from the preview or ask the agent to build the project as a website instead and open its published link on the phone; the same prompt works for both. Do the APK build the evening before, not the morning of, and keep a screen recording as a backup in case the venue Wi-Fi is bad.

What to say about how it was built

Be direct. Judges and teachers are more interested in your decisions than in who typed the code, and they will ask. A short, honest paragraph works well in the About screen and on your slide:

• "We designed the app: the audience, the screens, the question bank and the tests. We described it to an AI app builder, which wrote the React Native code, and we reviewed and changed it through 25 follow-up prompts."
• List two or three things the first version got wrong and how you fixed them. That is the part that shows understanding.
• If the rules ask for it, show the prompt history and open the code in the editor. Be ready to explain what a screen file does in general terms.
• Credit your data sources (the textbook the questions came from, the school timetable) and say where the data is stored (on the device).

Check the rules of the competition or the assignment before you start. Most hackathons allow AI tools and many require you to disclose them; some classes forbid them for specific assignments. If AI tools are not allowed, this is not the route to take.

What it costs, and a note for schools

At the time of writing the free plan includes 500K AI tokens a month with every feature and no card required; a free APK download is included. A small app takes a few hundred thousand tokens to build and iterate, so one focused project fits. To stretch it: write the prompt carefully, batch small changes into one message, and build the APK only when the app is finished. The Member plan is $1.49 per 30 days for 5M tokens, unlimited APK builds and source export, which matters if the assignment requires you to submit the code as a zip. Pro ($5.72) and higher plans add larger token allowances. Prices can change.

A few points for schools in the US, UK and EU. Sign-in is with a Google account, so check whether your school Google accounts allow third-party sign-in, or use a personal account. If the app collects anything about classmates (names in a leaderboard, a directory), keep it on the device, ask before adding people, and avoid collecting data from under-13s in the US or from children under the age of digital consent in your EU country; a project that stores nothing personal has nothing to explain. Projects are saved to your account and you can delete them after the presentation. For help while building, the Support panel in the builder reaches the team.

When you are ready, browse the quiz and learning apps for ideas on result screens, read the AI app builder page for what the builder can do, and paste your one-sentence idea. The best hackathon apps are the ones you finished.

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