20 Hackathon Project Ideas You Can Demo in a Weekend

Twenty hackathon project ideas for community, learning, climate, developer and AI themes, with who each is for, the demo to build and the hard part.

Mythex Team · 2026-10-22 · 7 min read

The best hackathon project ideas solve one specific problem for one specific person, and can be shown working, live, in under three minutes. That usually means a web app with one main journey: a form, a bit of logic or an API call, and a clear result on screen. Below are twenty ideas grouped by common hackathon themes, each with who it's for, the demo to build in 24–48 hours, what could make it a business afterwards, and the honest hard part. Pick one, shrink it, and spend the last quarter of the event on the demo.

If you want ideas to keep working on after the event, side project ideas you can build with AI and AI startup ideas go further. This list is tuned for a weekend.

Pick an idea that fits the event

If the event is about...	Strong ideas from this list	What judges tend to look for
Community and civic tech	1–4	A real local problem, clear users
Education	5–8	Students or teachers actually helped
Climate and sustainability	9–11	A measurable change, honest numbers
Health and accessibility	12–14	Care with data and safety
Developer tools	15–17	Saves developers real time
AI and APIs	18–20	Clever use of the model, not just a chat box

Always read the event's rules and judging criteria first; they decide more than the theme does.

Community and civic

1. Lost-and-found board for a campus or venue

For: Students, festival-goers, gym members.
Demo: Post a found item with a photo and location, search by category, and a "this is mine" claim flow that notifies the finder.
Afterwards: Venues could pay for a branded board; most will see it as a free service.
Hard part: Stopping false claims. A simple question only the owner could answer ("what's the phone case colour?") makes a good demo moment.

2. Volunteer shift matcher

For: Food banks, shelters and charities with a rota on paper.
Demo: The organiser creates shifts with slots; volunteers sign up on their phone; a dashboard shows gaps. The scheduling builder covers the core.
Hard part: Getting a real organisation to look at it. Bring a quote or a photo of the real paper rota to the pitch.

3. Accessible-places map for one town

For: Wheelchair users, parents with buggies, people with sensory needs.
Demo: A map of places with step-free access, accessible toilets and quiet hours, and a form to add or correct a place.
Hard part: Data you can trust. Show where each entry came from and when it was last checked.

4. Plain-language council decisions

For: Residents who never read meeting minutes.
Demo: Paste or upload a public agenda, get a short plain summary with what's being decided and when, and a "follow this topic" button.
Hard part: Accuracy. Show the original text next to the summary so people can check it.

Education

5. Study group finder for one course

For: Students in big classes who don't know anyone.
Demo: Pick your course and free times, see groups that match, and join one. The directory builder is a good base.
Hard part: Safety and privacy. Use university emails for login and don't show personal phone numbers.

6. Past-paper practice with instant marking

For: Students revising for one exam.
Demo: Multiple-choice questions by topic, instant feedback, and a weak-topics chart. See how to build a quiz app.
Afterwards: A paid tier with more questions could work, if you write your own.
Hard part: Copyright. Use questions you wrote or ones the exam board allows you to use.

7. Classroom exit-ticket tool

For: Teachers who want a quick "did they get it?" check at the end of a lesson.
Demo: Teacher creates a two-question check, students answer on a phone with a code, and the teacher sees a summary in seconds.
Hard part: Working in a real classroom: no logins for students under 13, and fast on bad school Wi-Fi.

8. Reading-level adapter

For: Teachers and parents of children reading below or above their age.
Demo: Paste a text and choose a reading level; an AI model rewrites it and highlights hard words with definitions.
Hard part: Keeping meaning intact. Show both versions side by side and let the teacher edit.

Climate and sustainability

9. Repair café booking and log

For: Community repair events.
Demo: People book a slot for an item, volunteers log what was fixed, and a page totals items saved from the bin. The events builder fits.
Hard part: Honest impact numbers. Count items repaired; don't invent carbon figures you can't back up.

10. Office or school energy dashboard

For: Facilities staff and eco-committees.
Demo: Upload meter readings (or a sample file), see use by day and room, and flag spikes. Start from the dashboard builder.
Hard part: Real data. If you can't get live meters, say so and demo with a clearly labelled sample.

For: Offices, halls of residence, community fridges.
Demo: Post leftover food with a photo and pickup time, get a notification, claim it. Items expire automatically.
Hard part: Food safety rules. Keep it to sealed or clearly labelled food and add a short guidelines page.

Health and accessibility

Be careful in this theme. A hackathon demo shouldn't diagnose or give medical advice, and you shouldn't use real patient data.

12. Medication reminder for carers

For: People who look after a parent or child with several medicines.
Demo: Add medicines with times, get reminders, tick off doses, and share a read-only view with a sibling.
Hard part: Reliability. A missed reminder matters; in the pitch, be honest that a demo isn't a medical device.

13. Clinic waiting-room queue

For: Walk-in clinics, pharmacies, advice centres.
Demo: Join the queue by scanning a code, see your position, get a message when it's nearly your turn.
Hard part: People without smartphones. Show how staff add them by hand.

14. Website accessibility checker for one issue

For: Small website owners.
Demo: Enter a URL, check one thing well (missing image alt text, or low colour contrast), and show the fixes.
Hard part: Depth over breadth. One check done properly beats twenty shallow ones. How to make your website accessible lists the basics.

Developer tools

15. API response mock server from an example

For: Front-end developers waiting on a back end.
Demo: Paste an example JSON response, get a live URL that returns it, with optional delays and errors.
Afterwards: Plenty of tools do this, so it's a learning project more than a business.
Hard part: Standing out. Pick one twist, like generating realistic fake data from the example.

16. Pull request summary for non-developers

For: Product managers who want to know what changed this week.
Demo: Connect a public repo (or paste a diff), get a plain-English summary of changes grouped by feature. What is GitHub covers the basics.
Hard part: Permissions. Use public repos in the demo, and never paste access tokens into the front end.

17. Environment variable checker

For: Teams who break deploys with a missing setting.
Demo: Compare an example config file to a real one (with values hidden) and list what's missing or unused.
Hard part: Never showing secret values. How to keep API keys safe explains why.

AI and API projects

These are popular, so the bar is higher. A chat box on top of a model isn't enough; show a specific job done better.

18. Receipt splitter

For: Friends sharing a restaurant bill.
Demo: Take a photo of a receipt, the app reads the items, everyone taps what they had, and it shows who owes what.
Hard part: Reading messy receipts. Let people fix mistakes quickly; that's part of the demo.

19. Meeting notes to action list

For: Student societies and small teams.
Demo: Paste notes or a transcript, get actions with owners and dates, and send them to each person.
Hard part: Wrong owners and invented deadlines. Show the source sentence for each action.

20. Voice-first form filler

For: People who find long forms hard: older users, people with dyslexia or low vision.
Demo: Speak answers to a form one question at a time; the app fills the fields and reads them back for confirmation.
Hard part: Getting consent right and never submitting without a final human check.

For any AI idea, you'll need an API key and the requests cost money; how to use LLM APIs explains keys, costs and limits.

How to win (or at least finish)

Write the demo script first. Three sentences: who the user is, what they do, what they see. Build only what the script needs.
Get the main journey working by halftime. Use templates, starter kits or an AI app builder for the dull parts: login, forms, database. A tool like Mythex can produce a working web app with a database and publish it to a link, which leaves your team time for the clever part. Check the event's rules on tools first.
Use realistic sample data. Ten believable entries make a demo feel real; "test test 123" doesn't.
Record a backup video. Wi-Fi fails at hackathons. A two-minute recording saves the pitch.
Show a real person's problem. A quote from someone you spoke to, or a photo of the paper process you're replacing.
Be honest about limits. Judges respect "this is sample data" more than a claim they can see through.

How to build an MVP in a weekend has more on cutting scope. If the project takes off after the event, how to validate an app idea is the next step.

Questions

What makes a good hackathon project?

A clear problem for a specific person, a demo that works live in two or three minutes, and one thing that's genuinely clever or well done. Judges usually remember the team that showed a real user's problem solved end to end, not the one with the most features.

How big should a hackathon project be?

Smaller than you think. Plan for one user journey: someone arrives, does the main thing, sees a result. Get that working by the halfway point, then spend the rest of the time on polish, the demo and a backup recording.

Can I use AI tools at a hackathon?

Usually, but check the event's rules. Some hackathons require code written during the event, ask you to declare tools and libraries, or have tracks with their own requirements. When in doubt, ask the organisers before you start.

What should a beginner build at a hackathon?

A simple web app with one form, a database and a results page: a sign-up sheet, a lost-and-found board or a study planner. Using an AI app builder or a template for the basics leaves time to focus on the idea and the demo.