Cookies & Storage
- Last updated
- 2 October 2026
- Applies to
- Everyone who uses the website
- Questions
- Please write to us.
The short version. We use no cookies for tracking, advertising or analytics — none at all. The site keeps a few small items in your browser’s own storage so that it works, and they stay on your device.
#What we store, and why
These are kept with your browser’s local storage and session storage, which, unlike cookies, are not sent to any server with each request. They are strictly necessary for the features you use, so they do not need your consent.
| Item | What it holds | How long |
|---|---|---|
learn:progress:v2 | Your learning progress: what you opened and marked understood, your last item, and the days you studied | Until you clear it, or sign out |
algorithms:lang | The programming language you last chose for solutions | Until you clear it |
sulba:entered | That you have already seen the opening animation in this visit, so it plays faster | Until you close the tab |
sb-…-auth-token | Only if you sign in: your sign-in session, so you stay signed in | Until you sign out |
sb-…-auth-token-code-verifier | Only while you sign in: a one-time code that keeps the sign-in secure | Until the sign-in finishes |
learn:consent | Only while you sign in: the version of the Terms you agreed to, until it is saved to your account | Until the sign-in finishes |
#Cookies set by others
We set no cookies. If you choose Continue with Google or Continue with GitHub, you briefly visit their sites, which may set their own cookies under their own policies. If you ask for a sign-in link by email or write to us through the site’s form, Cloudflare’s security check runs in a frame from challenges.cloudflare.com; anything it keeps in your browser is set by Cloudflare under its Turnstile privacy terms. GitHub, which hosts this site, does not use cookies on it for tracking.
#Your choices
- You can clear everything above at any time in your browser’s settings (usually under “site data”).
- Blocking storage will not break the site: your progress simply will not be remembered.
- Signing out removes your session and this browser’s copy of your progress.
Questions? Please write to us. See also the Privacy Policy.