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

static library

A bundle of object files copied into each program that links it.

A static library (.a on Linux and macOS, .lib on Windows) is an archive of object files; the linker copies the needed parts into the executable, so nothing extra ships at run time.