Practice

Learn by doing

Short, hands-on lessons - read the task, write real code, run it in your browser, and get checked instantly. No setup, no account.

SQL Practice B

Hands-on SQL lessons - write real queries against a live in-browser database and get checked instantly.

26 lessons 0/26 done

JavaScript Practice B

Hands-on JavaScript lessons - write real functions, run them instantly, and get checked by real tests.

21 lessons 0/21 done

Python Practice B

Hands-on Python lessons - write real code, run it instantly, and get checked by real tests.

22 lessons 0/22 done

HTML & CSS Practice B

Hands-on HTML and CSS lessons - write real markup and styles, watch the page redraw as you type, and get checked instantly.

12 lessons 0/12 done

Regex Practice B

Hands-on regular-expression lessons - write real patterns, run them instantly, and get checked by real tests.

14 lessons 0/14 done

TypeScript Practice B

Hands-on TypeScript lessons - add types to real JavaScript, run them instantly, and get checked by real tests.

12 lessons 0/12 done

Git Practice B

Hands-on Git lessons - type real git commands into an in-browser terminal, against a real repository, and get checked instantly.

9 lessons 0/9 done

Postgres Practice I

Hands-on lessons on the features real Postgres has beyond standard SQL - JSONB, arrays, RETURNING, upsert, CTEs, window functions, and recursive queries - against a real Postgres running in your browser.

12 lessons 0/12 done

Math Practice B

Hands-on arithmetic lessons - type a formula, run it, and get checked instantly. Order of operations, percentages, averages, and compound interest.

8 lessons 0/8 done

Physics Practice B

Hands-on physics lessons - plug real numbers into the formulas from the Physics guides (force, speed, free fall, momentum, kinetic energy) and get checked instantly.

8 lessons 0/8 done

Algorithms Practice B

Hands-on algorithm lessons - implement the classics yourself (binary search, bubble sort, two-sum, BFS) and get checked by real tests.

4 lessons 0/4 done