CSSBattle vs Eolymp

CSSBattle is a web game for practicing HTML and CSS by rebuilding target images with the shortest possible code. Scores reflect both visual similarity and character count. You can open targets and write code without an account, but logging in is required to submit and receive a score. A new Daily Target appears at 00:00 UTC; these daily challenges have no leaderboards. Battles use separate targets and leaderboards, while private Versus battles support one-on-one challenges with friends. Submissions cannot use JavaScript, SVG, images, or external assets, and are rendered in a headless Chromium browser on Ubuntu 18.04. Learn courses add interactive levels and quizzes for beginners, intermediate learners, and experts. The free plan permits only the current day’s target. PLUS adds more than 1,100 past Daily Targets, top solutions, plugins, statistics, search and sharing, unlimited history, and a VSCode editor. CSSBattle Free costs nothing; PLUS costs $4.90 a month or $59 a year.

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.