Who runs Battles, and why.

CodeKairo Battles exists so that a coding club can run a fair, judged tournament in an afternoon — without building a judge, renting one or settling results on a spreadsheet. This page is what it is, what it is not yet, and who builds it.

What is CodeKairo Battles?

CodeKairo Battles is a free tournament platform on which colleges, clubs and companies host coding competitions — 1v1 knockouts and ICPC-style team contests — judged live on CodeKairo's problem catalogue in 13 programming languages. An organizer creates an organization, has it verified by CodeKairo, and drafts a tournament: the format, the dates, who may enter — anyone, listed email domains, an invite code, the organizer's approval, or a mix — and up to 15 problems from a catalogue of about 600, each judged by hidden tests. In a knockout, players register themselves, check in during the hour before the start and are seeded by rating into a bracket where every match is one problem against the clock. In an ICPC-style contest the organizer enters teams of up to three, and the scoreboard ranks by problems solved and penalty time, with an optional freeze before the end. Players use the account they already have on CodeKairo, and every accepted solve counts on their CodeKairo profile. Hosting is free.

Organizers: coding clubs, student chapters, college departments and placement cells, and companies running a campus or community contest — anyone who wants a judged event without building or renting a judge. Players: students and developers who want to compete for their college or club on the account, the editor and the 13 languages they already practise in.

Five rules the site keeps.

  • The judge decides. Every verdict comes from running code against the same hidden tests. Organizers choose the settings — the format, the dates, the problems — never how a result is reached.
  • Rules before the first match. Seeding, byes, tie-breaks, penalty minutes and the freeze are written down on one page, numbered and applied by the code, so a dispute can cite rule 2.6 rather than someone's memory.
  • Entrants keep their addresses. An organizer checks eligibility against the domain of an entrant's email and never sees the address; brackets and scoreboards stay out of search.
  • Public once checked. Anyone can draft a tournament, but none goes public until a person at CodeKairo has checked the organization behind it.
  • A result belongs on your profile. Solves count on the CodeKairo profile you already practise on, and every tournament you play stays in your record.

Everything here is live today.

If a feature is described on this site, you can sign in and use it. If it is not here, it has not been built.

  • 1v1 knockouts. Check-in, seeding by rating, byes for the top seeds, one problem a match on a clock, both sides' progress live, and a champion.
  • ICPC-style contests. Teams of up to three, penalty minutes, a scoreboard that can freeze for the last stretch, and the reveal.
  • Who may enter. Open to anyone, or limited by email domain, invite code or the organizer's approval — in any mix — with an optional cap on places.
  • Verified organizers. Checked by a person before they go public, and again when they change — with a public page listing their tournaments.
  • Team upload. Up to 500 teams pasted in one go, checked as a whole, every problem reported by line.
  • One account, 13 languages. Sign in with email, Google or GitHub and solve in the CodeKairo editor; accepted solves count on your profile.

Built by CodeKairo.

Battles is built and run by CodeKairo, the coding-practice platform at codekairo.com, on its accounts, its judge and its catalogue of about 600 problems. CodeKairo is built by one founder, so the person who reads a report about a tournament is the person who can fix it.

Write to support@codekairo.com about an account, a tournament or your data, and to contact@codekairo.com about anything else — a partnership, a large event you want to plan, the press.

Every way to reach us · About CodeKairo

What it does not do yet.

  • Two formats, for now. 1v1 knockouts and ICPC-style contests. Team duels, Swiss rounds and hackathons are not built yet.
  • Catalogue problems only. A tournament draws on CodeKairo's catalogue of about 600 judged problems. Writing your own is not supported yet.
  • No proctoring. Rooms are not proctored and there is no plagiarism check. Organizers set their event's conduct rules and enforce them.
  • No tournament emails. Approvals, check-in and match calls appear on the site, not in your inbox — keep the tournament page open on the day.
  • A shared judge. Comfortable for a club night. For more than about 50 people submitting at once, write to us before you publish.
  • English only. The site, the rules and the problems are in English.