DMOJ vs Eolymp

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.

Eolymp provides tools for creating and hosting programming competitions and learning activities, from small practice rounds to official contests the maker says can involve thousands of participants. Organizers can run synchronized online contests or virtual contests with individual timers, then allow upsolving. Contests support IOI scoring with partial credit and ICPC scoring with time penalties. Problem-authoring tools cover statements, tests, checkers, solutions, validators, interactors and generators; problems can also be imported from Basecamp or Polygon. Courses bring together modules, learning materials, assignments and grades. The API uses HTTPS and JSON, offers API-key or OAuth 2.0 authentication, and has SDKs for Python, Go, PHP and JavaScript. Each space can connect supported AI clients through an MCP server, subject to the signed-in user's permissions. Free Services cost nothing and include problem materials, competition access and automatic solution testing. A new space can be tried free for 30 days with five seats and no payment details to start.