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

Release build

An optimized build meant for real use.

A Release configuration enables optimization (for example -O2/-O3 or /O2) and usually defines NDEBUG, which turns assert off; it runs faster and is harder to debug.