What you’ll build

Server-owned validation, input ordering, independent HTTP tests, integrity checks, replay, detector evaluation and recovery for an owned toy arena.

Before you start

JavaScript familiarity. The full course runs locally with Node.js 22 or later. Guided decisions work at phone widths; source editing and HTTP tests need a workstation. A separate browser movement model is available to try first.

Beta: human learning and completion time are unvalidated; native 200% zoom and VoiceOver are untested; historical generator model IDs are unavailable. The 12–23-hour range is an author planning estimate. These are teaching models, not production security or a job qualification.