We built Promsob to collect as little data as possible — here's what we store and why.
By default, Promsob runs entirely in your browser. The app stores your settings (language, difficulty, mode, text-to-speech, etc.) in browser cookies and your quiz statistics and answer history in your browser's localStorage.
This data stays on your device and is never sent to our servers. Clearing your browser data removes it.
If you choose to create an account, our server stores only: a display name, your passkey (WebAuthn) public-key credentials, and a session token for login. No email address is required or stored.
The site uses Google Analytics 4 (GA4) by Google. Google receives visit data such as the pages you view, device and browser information, and your IP address, and sets its own cookies. This is governed by Google's privacy policy, and you can opt out using Google's Analytics opt-out add-on.
We do not sell your data or share it with third parties, except as described above (Google, for analytics).