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

lock ordering

Taking locks in one agreed order everywhere, so no cycle of waiting can form.

Every path that holds more than one lock acquires them in the same total order, such as ascending account id, which removes circular wait.