The data format behind almost every app — made readable.

JSON is how programs save and send information. This free lesson teaches you to read it, edit it by hand in Notepad, fix it when it breaks, and use a tiny to-do list app that stores everything as JSON.

What you’ll learn

• Curly braces, square brackets, keys and values — in plain words
• Editing a JSON file safely in Notepad
• Spotting and fixing the 5 most common JSON mistakes
• Using a small to-do app (add, list, done)
• Restoring from a backup when things go wrong

What you get

• A step-by-step course with real screenshots
• A 30-second explainer video
• todo.py, sample JSON files and a backup

Who it’s for: beginners who’ve done What is Python?

Time: about 15 minutes.

Next lesson: What is a GPU?