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

carrier thread

A platform thread that a virtual thread is mounted on while it runs.

Carriers are a small ForkJoinPool of platform threads, about one per core; a virtual thread is mounted on one to run and unmounted when it blocks, and may resume on any carrier.