AlgoJudge is open-source, self-hosted software for programming contests and courses, with automatic evaluation of submitted solutions.

It is built for the range of activities a department actually runs — contests, courses, laboratories, training sessions — rather than for one of them.

• Information site: algojudge.pl
• Documentation: docs.algojudge.pl
• Application domain: algojudge.app

Most online judges fix one kind of activity and one kind of problem in the core. AlgoJudge separates three concerns and holds the line between them:

• the Client renders an activity or problem type,
• the Runner executes and evaluates a submission in isolation,
• the Server stores a shared, versioned data envelope and never interprets what a type means, nor compiles or runs any submitted code.

The goal is that adding a problem type needs a Client renderer and a Runner handler, not a change to the Server. That is tested rather than asserted, twice:

• a second problem type, output-only@1, where the participant uploads answers instead of a program, lives entirely in the Runner and appears nowhere in the Server's source or in its OpenAPI document;
• a second Runner implementation, which judges nothing and forwards submissions to an external judging system, registers, claims and reports over the same contract as the first — which is the point of having a contract.

0.2.0 is released. Six repositories carry v0.2.0, and the eight images an installation needs are on ghcr.io/algojudge and pull without a token. 0.2.0 breaks compatibility with 0.1 on purpose, and its release notes say what an installation has to do to upgrade.

The Server holds the domain model, the permission model, the API and the operator surface; the Client is wired to it throughout, in Polish and English; the Runner compiles, runs and grades real submissions under isolation, with an adversarial suite that gates every merge. The deployment target is a self-hosted Docker Compose stack, which AlgoJudge-Ops is: it holds no application code and builds nothing, pulling every image by tag, so an update is docker compose pull and a rollback is a digest.

The documentation is published in English and Polish and is versioned by section, because the parts release independently: /en/install/v0.2/ is the 0.2 line, and /en/install/v0.1/ still describes 0.1. Nothing is written after the fact — a version's pages are copied on release day or not at all, since for an installation that has not upgraded the old page is the only one that still describes it.

A 0.x release promises no backward compatibility. Every minor release says what broke and what to do about it.

The code is MIT. The documentation pages in AlgoJudge-Docs and AlgoJudge-Ops are CC BY 4.0, with the code samples on them staying MIT so that pasting a command obliges nobody.