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Interactive coding lessons

Pause the lesson.
Change the code.
Watch it run.

Every lesson is live code, not a video. Stop the teacher anytime, edit their project in your browser, and pick up right where you left off.

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No installs. Works on any laptop with Chrome, Edge or Firefox.

How a lesson works

  1. Watch the teacher code

    You see their editor, their browser and their terminal — real code, typed live.

  2. Type to take over

    Type in the teacher’s code. It pauses and becomes your own fork. Change anything, run it, break it.

  3. Solve the challenges

    The lesson stops for small tasks. Checks tell you exactly what works and what doesn't.

Start with a project

All courses

Everything runs in your browser

Front-end, back-end, databases and Python — with a real terminal, a preview with an address bar, and an API client. Nothing to install, nothing sent to a server to run.

  • JavaScript & TypeScript
  • React & Next.js
  • Node & Express
  • SQL & databases
  • Python
  • PHP & Laravel

Your first lesson takes five minutes

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