Niio: Period Tracker
Effective 8 August 2026 · Last updated 10 August 2026
This policy explains how the Niio: Period Tracker mobile app ("Niio", "the app", "we") handles information. It applies to the Android and iOS versions of the app, and to nothing else — we operate no website accounts, newsletters, or other services tied to it.
Niio stores the following on your device so it can show your history and predict your next cycle. You choose what to enter; every field is optional.
| Information | Why the app keeps it |
|---|---|
| Period dates and flow intensity | Calculating cycle length, showing the calendar, predicting your next period |
| Symptoms, moods, energy, sleep quality | The patterns and correlations shown on the Insights tab |
| Personal notes | Displayed back to you on the day you wrote them; never analysed |
| First name or nickname | Greeting you on the Today tab |
| Birth year | Age-appropriate cycle estimates |
| Onboarding answers | Your goal for using Niio, how you were feeling, and whether your cycle is usually regular — these tailor what the app shows |
| Premium status | Remembering that you subscribed, so the app stays ad-free after a restart |
Technically, the daily logs live in a private SQLite database (daily_logs) inside the app's own storage, and the remaining settings live in the platform's standard app-preferences store. Both are sandboxed by Android and iOS: other apps cannot read them.
Niio has no backend. There is no login, no cloud sync, no backup service, and no analytics SDK in the app.
That is not a promise about how carefully we guard your data — it is a description of the architecture. Your cycle history is never transmitted anywhere, so the developer has no copy of it, no way to look at it, and nothing to hand over if asked.
If you switch reminders on, Niio schedules notifications for the days it predicts — your next period, your fertile window and your estimated ovulation day.
These are scheduled by your own device from dates already stored on it. There is no push service, no notification token and no server involved, so nothing about your cycle leaves the phone in order to remind you about it.
The free version of Niio shows advertising supplied by Google AdMob. To serve and measure those ads, Google may collect and process:
This is handled by Google under Google's Privacy Policy, not by us. We receive only aggregate revenue figures — never information about an individual person.
You can limit ad tracking at any time: on Android, under Settings → Privacy → Ads, where you can delete or reset your advertising ID; on iOS, under Settings → Privacy & Security → Tracking. Subscribing to Niio Premium removes all advertising from the app.
Niio Premium is sold as an auto-renewing subscription. Purchases are processed entirely by Google Play Billing on Android and the App Store on iOS.
We never see or store your card number, billing address, or any other payment detail. The app receives only a signal from the store confirming that a valid subscription exists, and records that as a single yes/no flag on your device. Manage or cancel your subscription in the Google Play or App Store subscription settings — cancelling there stops all future charges.
Uninstalling Niio removes the app's database and settings from your device, and with them everything described in section 02. No copy remains, because no copy was ever made elsewhere.
If your device is set to back up app data automatically (Android Backup or iCloud), a copy may exist in that system backup under your own account. That backup is controlled by you through your Google or Apple settings; we have no access to it.
Niio is not directed at children under 13, and we do not knowingly collect information from them. Younger users who track their cycle should do so with a parent or guardian's involvement.
Predictions in Niio are statistical estimates calculated from the dates you enter. They are not a diagnosis, and they are not a contraceptive method — do not rely on the fertile window or ovulation day shown in the app to prevent or achieve pregnancy. Cycles vary for many reasons, and the app cannot know about yours.
For anything concerning your health, talk to a qualified healthcare professional.
If the app starts handling data differently — for example if cloud sync or an account system is ever added — this page will be updated before that version ships, and the "last updated" date above will change. Material changes will also be noted in the app's release notes.
Questions about this policy or about your data can go to ninhdevelop.io@gmail.com. We aim to reply within a few business days.