Privacy
Five Nines (fivenines.uk) is a game for learning system design. Its source is public at github.com/ya-nsh/fivenines. This page says what data it handles and why.
If you don’t sign in
Your players and progress are saved only in your browser’s local storage, on your device. Nothing about your progress is sent to us. Clearing your browser’s site data deletes it; use Export save file in the player menu to keep a copy.
If you sign in with Google
Signing in is optional. It syncs one player to your account so your progress follows you between devices.
- From Google we receive your email address, name and profile picture link. We ask Google for nothing else.
- Your progress for the synced player is stored in our database: its name, levels, scores, designs and drafts, notes, review cards, kata code and settings.
- Your account and progress are stored with Supabase, which provides our database and sign-in. Only you can read your saved progress.
We use this only to sign you in and sync your progress. We don’t show ads, sell data, or share it with anyone else.
Every visit
- The site is hosted by Vercel, whose servers keep standard request logs (such as IP address and browser) for security and reliability.
- Fonts load from Google Fonts, so your browser contacts Google’s font servers.
- There is no analytics or tracking.
Deleting your data
Open the player menu and choose Delete account. Your account and cloud save are deleted immediately. Players on your device stay there until you delete them from the same menu. Supabase may keep database backups for a short time before they expire.
Sign out only signs this device out; your cloud save stays in your account.
Questions
Open an issue at github.com/ya-nsh/fivenines/issues. If this policy changes, the date above changes with it.