Privacy Policy

StackDrill · Last updated 1 July 2026

StackDrill is a flashcard trainer for memorised card stacks. This policy explains what data the app handles. In short: the app has no user accounts, shows no ads, and includes no analytics or tracking.

Data stored on your device

By default, everything StackDrill records — your learning progress, drill statistics, custom stacks, and any pegs or notes you write — is stored locally on your device only. It never leaves your device unless you choose to enable Sync (below). Deleting the app removes this data.

Optional cloud sync

StackDrill offers an optional Sync feature so you can carry your progress between your own devices. Sync is off unless you turn it on. When you enable it, the app generates a random, anonymous sync code and stores a copy of your progress data (the same statistics, stacks, pegs, and notes described above) in a hosted database provided by Supabase, keyed to that code.

• No name, email address, account, or other identifying information is collected or required.
• The sync code is the only key to your data. Anyone who has your code can read the synced progress, so treat it like a password and don't share it.
• You can rotate your code or turn Sync off at any time from the app's Settings. Turning Sync off stops further uploads; you can also change your code, which retires the old one.

What is not collected

StackDrill contains no advertising, no third-party analytics or tracking SDKs, and does not collect your location, contacts, device identifiers, or any personal information.

Children's privacy

StackDrill does not knowingly collect any personal information from anyone, including children.

Changes to this policy

If this policy changes, the updated version will be posted at this URL with a revised date.

Contact

Questions about privacy? Email oscar@sullivanltd.co.uk.