Open source hackathons
5 open open source hackathons, each checked against the organizer's official page. 1 closes in the next 7 days.
A hackathon gives you a deadline, a theme and a prize pool. Many run online for several weeks and accept solo builders, so you can enter from anywhere and work in your own time.
Money for people who write and maintain open source: foundation grants, security funds, maintainer stipends and paid contribution programs.
Hacktoberfest Weekend Challenge 2026: Build for a Friend
DEV pays $250 for a new project that uses open source AI to help a real person. Submit on DEV by 5 October 2026.
Hack Apertus Online 2026
Online hackathon to test and build on Apertus, the open Swiss LLM. Four track winners get CHF 2,500 each. Submit by 16 October 2026.
OpenCV AI Competition 2026, powered by AWS
The OpenCV AI Competition 2026, sponsored by AWS, pays $20,250 in prizes and compute grants for computer vision projects. Entries close on October 26, 2026.
Tari October Build Contest 2026: Spooky Secrets
The Tari Council pays 1,000,000 XTM for the best new privacy project on Ootle. Entries close at 00:00 UTC on 1 November 2026.
ARC Prize 2026
ARC Prize 2026 offers $2M in prizes across three tracks for open source progress on the ARC-AGI benchmarks. Submissions on Kaggle are due November 2, 2026.
Questions
How many open source hackathons are open right now?
5 as of 5 October 2026. 1 closes in the next 7 days.
Which open source hackathons close soonest?
Hacktoberfest Weekend Challenge 2026: Build for a Friend from DEV closes on 5 October 2026. Hack Apertus Online 2026 from aiLights Association closes on 16 October 2026. OpenCV AI Competition 2026, powered by AWS from OpenCV Foundation closes on 26 October 2026.
Can I apply from any country?
All of them accept applicants worldwide. Some still set conditions on age, residence or sanctions, and each entry lists them.
How is this list checked?
Every entry is written from the organizer's official page and links to it. Programs with a rolling deadline are checked again for closure, and an entry moves to the archive on the day it closes.