Luna Cycle: Privacy-First Menstrual Tracking

Luna Cycle is a menstrual cycle tracker built the way a privacy-conscious Android app should be: your data lives on your device, the app works completely offline, and cloud sync is an optional switch you control.

No account required. No ads. No analytics. No tracking SDKs.

Calendar At-a-Glance
A clean monthly calendar shows logged period days, predicted cycles (dashed), fertile-window estimates, and today — all using Material 3 semantic color tokens that adapt to your Android 12+ wallpaper.

Daily Log
Log what you actually want to log, and skip the rest. Flow intensity, mood, symptoms, energy, sleep hours and quality, plus free-text notes. Eight built-in symptoms and support for up to 20 custom tags.

History & Statistics
Rolling 6-cycle averages, typical period duration, longest and shortest cycles on record, and a simple 12-cycle bar chart — enough to spot patterns without drowning you in dashboards.

Local Reminders
Forecast nudges 0–7 days before your predicted period, a daily-log reminder at the time you choose, and optional medication alarms. Everything runs on-device via AlarmManager — no push servers, no network required.

App Lock
Optional PIN (4–6 digits) or biometric unlock with configurable auto-lock. There is deliberately no "forgot PIN" recovery path; privacy is the priority.

Your Data, Your Format
Export everything as CSV or JSON at any time. Import a JSON backup on a new device for fully offline restores. Nothing is ever locked in.

Optional Cloud Sync
If you want your data on multiple devices, turn on sync with a Google account or email + password. Data is scoped per user and protected by Firestore security rules so nobody — including us — can read another user's data. Turn it off at any time and keep working locally.

Material You
Built from the ground up with Jetpack Compose and Material 3 Expressive. On Android 12+ the entire palette is derived from your wallpaper via dynamic color. Home-screen widgets use Jetpack Glance so they match too.

Adaptive Layouts
On tablets and large foldables the calendar and daily log share a list-detail pane. On phones they stack. One app, right-sized for every screen.

Luna Cycle is a tracking tool, not a medical device. Cycle predictions and fertile-window estimates are calendar-based calculations only and are not a substitute for medical advice. Do not rely on the app for contraception or fertility planning.