Features

Everything you need to actually learn to code.

502 topics, 2,565 questions with a note on every option, and 285 coding challenges, wrapped in a calm app that remembers what you need to review.

Learning

Lessons that teach one idea at a time.

Explanation cards with text and code, then an editor holding a runnable example to change and run again.

A recap of the key points, then questions. Missed questions come back at the end.

Every unit collects its cards in one place, so you can look something up any time.

What does this print, multiple choice, fill in the blank, and build a line from tokens.

Remembering

Right answers push the next review out (1, 3, 7, 16, 35, 75 days); wrong ones bring it back tomorrow.

Up to 15 due questions a day, mixed across the course.

Questions you have seen before are asked as typed answers instead of choices.

Review templates use new values each time, with outputs checked by actually running the code.

Proving it

20 shuffled questions. Three mistakes and it starts over, so passing means you know it.

Write a program from an empty editor and check it against tests. Stuck twice? Peek at a solution.

100 items including 15 challenges that mix topics. Your place is saved after every step.

Questions that need working out get a small calculator, with % as the remainder like in code.

Help and motivation

Ask about the card, question or your code. It gives hints, never full solutions to challenges.

A daily streak and XP for every lesson, quiz and review keep you coming back.

Saved on your device and backed up, so it follows you from phone to browser.

An Android app and a web app with the same courses and the same progress.

Pick a course and finish your first lesson in a few minutes.