Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

🐛

Bug-Hunt Time Trial

Two minutes. Each function has one bad line: a range one short, count = 1, sort() that returns None, a missing dict key. Find it.

⏱️ 120s

▶ Log in to play

← Back to the arcade