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

relational database

A database that stores data in tables of rows and columns, linked by keys.

A relational database organizes data into tables (relations) with typed columns, keys and constraints, queried with SQL.