what is a hackathon?

the short definition

A hackathon is a competition with a deadline. Organisers set a theme and a time limit, participants form teams, and every team spends that time turning an idea into something that runs. At the end each team demonstrates what it built, judges score the entries against published criteria, and prizes go to the strongest.

Four things make an event a hackathon rather than a workshop or a conference: it istime-boxed, work happens in teams, the output is somethingbuilt during the event, and it is judged.

what the word means

“Hackathon” joins hack and marathon. “Hack” is used in its older engineering sense — solving a problem quickly and inventively — and not in the sense of breaking into systems. “Marathon” describes the format: one continuous, fixed block of time rather than a series of sessions. So the word literally describes a long, uninterrupted stretch of inventive building, which is what the event is.

how a hackathon runs

The order is close to the same everywhere:

• Kickoff — the organiser sets out the theme, the rules, the judging criteria and the deadline.
• Team formation — people either arrive as a team or form one on the spot.
• Building — the bulk of the time, usually with mentors on hand.
• Submission — work stops at a hard deadline and teams submit whatever state their project is in.
• Demos — each team presents, typically in a few minutes.
• Judging and prizes — judges score against the criteria set at kickoff and announce winners.

how long they last

There is no standard length — the organiser sets it. Of the 45 hackathons listed on this site right now, 39 run inside a single day and 6 run across two or more. The longest currently listed is 2026 Joint International Bioinformatics Hackathon – Cambridge, which runs 3 days (9-11 Sep 2026).

Shorter events are usually built around a single narrow brief you can finish in an evening or an afternoon. Longer ones leave room for a bigger build, and normally include food, sleep and mentor sessions in the schedule.

the types you'll see listed

Hackathons are usually named for their subject or their audience. These are the filters this directory keeps, with what is on each right now:

Events are also split by format — in person, online or hybrid — and by city. You can browse every listing by city from the locations index.

who can enter

Hackathons are open to more than programmers: teams that win are usually a mix of engineering, design and someone who can present the idea clearly. Plenty of events are aimed squarely at people who don't write code, and say so in their own description.

If it's your first one, the practical advice is to scope small. A finished small idea demos far better than an ambitious half-built one, because judging happens on what actually runs.

what you can win

Prizes are set per event and published on the listing. They are not always cash — mentoring, credits, hardware and introductions are common — and the amount varies enormously between a community jam and a sponsored event.

faq

find one to enter

This site lists every upcoming hackathon it can find in the UK, updated daily. Browse all 45 upcoming events, narrow to AI hackathons, student hackathons, datathons or game jams, or pick a city from the locations index.

Running one? Submit your hackathon — free to list.