What is a cookie?
A cookie is a small file a website stores in your browser to remember things about you — like whether you're logged in, or your preferred language. Some cookies are essential; others help us understand usage.
Cookies we use
Strictly necessary (always on)
- Session cookies (auth token, session ID) — required to log in and stay signed in.
- CSRF tokens — protect against forged requests.
- Load-balancer cookies — route your requests to the right server.
Preferences (opt-in)
- Language, theme, font size, and last-visited page.
Analytics (opt-in)
- Aggregate usage stats — which lessons are popular, where users get stuck. Never used for ads.
Managing cookies
You can clear or block cookies from your browser settings. Blocking essential cookies may break login and lesson delivery. You can opt out of analytics from your account settings.
Third-party cookies
We use minimal third-party cookies (payment processor, error monitoring). See our Privacy Policy for the full list of sub-processors.