DMOJ vs PrairieLearn

DMOJ is an open-source platform for programming contests and an archive of programming problems. Its archive includes tasks from past CCC, CCO, COCI, IOI and JOI competitions, among other sources, and it runs a monthly open programming competition. Public contests can be hosted at no cost. Contest formats include ICPC, IOI, AtCoder and ECOO, with system testing, hidden scoreboards and virtual participation. Judging supports interactive and signature-graded tasks, runtime data generators, custom output validators, per-language resource limits and scaling to hundreds of judging servers. Problem statements can include Markdown, LaTeX math and figures, syntax highlighting, PDF generation and built-in editorials. DMOJ integrates with Stanford MOSS for plagiarism checking and supports OAuth login, two-factor authentication and fine-grained staff permissions. Documentation is available for self-hosting the site and judge; the installation guide says the site is tested with MySQL and is unlikely to work with other databases. AI use is prohibited in rated contests, and judging resources cannot be used for AI training.

PrairieLearn is an online assessment and learning system for instructors creating educational resources, assignments, practice, and tests. Instructors write questions as code; the system can generate and grade variants automatically and provide real-time feedback. Students can continue trying new variants until they achieve mastery. Supported response formats include numerical, multiple-choice, checkbox, dropdown, graphical, code, and ordered-block answers. The platform is described for in-class activities, homework, practice, proctored tests, and bring-your-own-device tests. It connects with learning management systems through LTI 1.3 for assignment linking and grade syncing, with integration primarily designed and documented for Canvas; its importer accepts QTI 1.2 content. PrairieLearn is open source and can be run or modified on institutional or individual infrastructure. The free plan covers instructors and courses with up to 20 students in each term. For larger courses, Basic costs $8, paid once per student and Premium costs $16, paid once per student. Local development is supported on macOS, Linux, or Windows inside WSL 2; Windows without WSL 2 is not supported for local installation.