A hackathon is a competitive programming event in which individuals or small teams are given a small window of time (usually between a day and a week) to design and implement a prototype computer application or service. Hackathons are often associated with conventions, corporations, cities, and colleges, all of whom tend to have a readily-accessible pool of programmers looking for a challenge. In the cases of corporations and cities, these hackathons are often oriented around promoting a new service or technology to the development community.

Hackathons should not be confused with code sprints, which are similarly fast-paced but focus on improving one specific application or service.