Cookie Policy

Last updated: 30 October 2026.

What we use today

• Local storage (essential to features you request). Your completed lessons are stored in your browser so your progress is remembered. This stays on your device.
• Sign-in storage (only if you sign in). Firebase Authentication stores a sign-in session in your browser so you stay signed in.
• Local storage (optional analytics). Only if you choose Allow in the analytics notice, Mixpanel keeps a random id and a few settings in your browser's local storage, not in a cookie, so it can recognise the same browser between visits. Your choice itself is also remembered in local storage. Choosing "turn off" in the footer clears the id.
• Session storage (visit counts). To count a visit once rather than for every page, your browser keeps a short note in session storage. It holds no information about you and disappears when you close the tab. It is not a cookie and is not used to follow you between visits.
• Browser cache (Python practice). The Python engine downloaded for the Run button is stored in your browser's normal cache so it loads faster next time. It is not a tracking cookie.

We do not set advertising or analytics cookies. Optional analytics use local storage and only run if you allow them. Our anonymous visit counts do not use cookies or any identifier that follows you, and they are skipped when your browser sends a Do Not Track or Global Privacy Control signal.

If this changes

If we add advertising or any other tracking, we will show a consent choice before loading them where the law requires it, explain what they do here, and let you change or withdraw your choice at any time.

Your choices

You can delete stored data through your browser's settings. If you do, your device-only progress will be lost.