Your cycle.
On your device.
Luna Cycle is an offline-first period tracker for Android. Everything you log stays in your own SQLite database — no account required, no analytics, no ads. Cloud sync is an optional opt-in you can toggle on or off at any time.
Everything you need. Nothing you don't.
Luna Cycle is a deliberately small app. It does period tracking well and stays out of the way.
Offline-first, by design
Room (SQLite) is the source of truth — your data never has to leave the device. Firebase sync is strictly opt-in and can be disabled without losing anything.
Calendar with predictions
Monthly calendar with logged days, predicted periods (dashed), fertile window, and a subtle today ring. Swipe between months or jump to today instantly.
Daily log
Track flow, mood, symptoms, energy, sleep hours + quality, and free-text notes. Add up to 20 custom tags for anything the defaults miss.
History & statistics
Rolling 6-cycle averages, period duration, longest/shortest cycles, and a 12-cycle bar chart — enough to spot patterns without overwhelming you.
Gentle reminders
Period forecast reminders (0–7 days ahead), daily-log nudges, and medication alarms. All local — no push servers, no network required.
App lock
Optional PIN (4–6 digits) or biometric unlock with configurable auto-lock. Deliberately no “forgot PIN” recovery — privacy over convenience.
Your data, your format
Export cycles and logs as CSV or JSON. Import a JSON backup on a new device for fully-offline restores. Nothing is ever locked in.
Material You
On Android 12+, the whole app takes colors from your wallpaper via dynamic color. Home-screen widgets use Jetpack Glance to match.
See it in motion.
Five screens from the shipping app. Dynamic color means yours will almost certainly look different — and that's the point.
Adaptive layout for every size.
On tablets and foldables, the calendar and daily log share a list-detail pane. On phones they stack naturally. One codebase, built around Compose's adaptive navigation.
Privacy isn't a feature. It's the foundation.
Most period trackers monetize your data. Luna Cycle takes the opposite approach: if you never sign in, nothing ever leaves your phone.
- Zero analytics in v1. No Firebase Analytics, no Crashlytics, no third-party SDKs beyond Auth and Firestore — and those only run when you opt into sync.
- Per-user isolation. If you do sync, Firestore security rules reject any request for another user's documents. No admin reads.
- Your data is yours. Delete all remote data from Settings at any time. Export as CSV or JSON whenever you want a copy.