FlashBlock privacy policy
FlashBlock is a local-first study tool. The short version: everything you create stays on your own device, and nothing is ever sent anywhere.
Last updated 29 June 2026
Where your data lives
Everything FlashBlock stores — your cards, decks, schedule, and settings — lives on your own device in an on-device SQLite database (compiled to WebAssembly). Your data never leaves your computer.
What FlashBlock does not do
- No account or sign-in
- No cloud sync
- No analytics or usage tracking
- No telemetry or crash reporting
- No remote backup
- No third-party sharing or advertising
Why FlashBlock asks for its permissions
Firefox requires you to approve two permissions at install. They exist solely to render the study overlay — never to read or transmit the pages you browse.
- Access browser tabs To show the review overlay in whichever tab you're looking at when cards come due.
- Access your data for all websites Only to draw the study overlay on top of the current page. FlashBlock never reads, stores, or transmits the content of the pages you visit.
Backups and exporting your data
You can export your data manually from the add-on for your own backup; FlashBlock never backs it up for you.
Uninstalling
Removing the add-on from Firefox deletes its on-device database and all associated data.
Contact
Questions about privacy? Email privacy@webinventions.com.au.