Privacy Policy
Effective October 8, 2026
The short version
Lumen does not collect, store, share or sell any personal data. There are no accounts, no ads, no analytics and no tracking. Everything you do in Lumen stays on your device.
This policy covers the Lumen iPhone app and the browser version at correll.github.io/lumen-ios, both made by Nikolaus Correll (“I”, “me”).
What stays on your device
To keep your game going, Lumen saves the following on your device only:
- your progress on today's daily window
- your statistics and streak
- your hint balance
- the gallery of windows you've restored
- your settings, such as sound and reminder time
This information is never sent to me or anyone else. In the iPhone app it is kept in the app's own storage. In the browser it is kept in your browser's local storage for this site. You can erase it at any time by deleting the app, or by clearing this site's data in your browser.
Notifications
If you turn on a daily reminder, Lumen schedules a local notification on your iPhone at the time you choose. Reminders are created and delivered entirely on your device. No push notification service or server is involved, and you can turn reminders off at any time in Lumen's Settings or in the iPhone Settings app.
Sharing
When you tap Share Result, Lumen hands a result image and text to the iPhone share sheet (or your browser's sharing feature). Nothing is shared unless you choose where to send it, and Lumen does not see what you share or with whom.
No third parties
Lumen contains no third-party analytics, advertising, crash reporting or tracking code, and it makes no network requests while you play. Its fonts and images are bundled with the game.
Website hosting
The browser version and these pages are hosted on GitHub Pages. When you visit them, GitHub may process technical information such as your IP address to deliver and secure the site, as described in the GitHub General Privacy Statement. I do not receive or use that information.
Children
Lumen is suitable for all ages. Because it collects no personal information from anyone, it collects none from children.
Changes
If this policy changes, the new version will be posted on this page with a new effective date.
Contact
Questions about privacy? Open a request at github.com/correll/lumen-ios/issues.