Open Period Tracker

A free, open-source period and cycle tracker for iOS and Android. It works offline, needs no account, shows no ads, and keeps your data on your device.

• App Store: https://apps.apple.com/us/app/open-period-cycle-tracker/id6761253443
• Google Play: https://play.google.com/store/apps/details?id=com.brandbuilder.periodtracker
• Website: https://onepiece92.github.io/openPeriodTracker/
• Privacy policy: https://brandbuilder.com.np/privacy-policy-for-open-period-cycle-tracker/

Store title: Open Period & Cycle Tracker. Built by Brand Builder with Flutter. MIT licensed.

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Screenshots

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What it does

Track

• Log periods and flow (light, medium, heavy) on a calendar
• Record moods (20 to choose from), symptoms and notes for any day
• Doctor's checklist: pain, discharge, skin, hair, sleep, libido, digestion, breast changes, energy, weight
• Period history and a comparison of the current cycle against your average

Predict

• Next period, fertile window and peak day on the calendar and home screen
• An on-device LSTM model (TensorFlow Lite) refines cycle length and period duration predictions from your own history
• 7-day phase forecast and symptom forecast from past cycles
• Optional reminders before a predicted period

Understand

• Insights: best and worst cycle days, weekly logging score, phase-based tips drawn from your own logs
• Analytics: cycle length trends, mood and symptom frequency, phase correlations
• Diet & Nutrition: phase-aware foods, macro and hydration guides, supplement suggestions, and regional food picks if you grant location access
• Yoga: poses and breathwork matched to each phase, with links to practice videos on YouTube
• AI prompt builder: generate an anonymised summary of your logs to paste into ChatGPT, Claude or Gemini

Keep control

• JSON backup and restore
• Demo data generator (one year of realistic data) to explore the app
• Three-step onboarding, skippable

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Privacy, stated plainly

• All data is stored in a local SQLite database on your device. The app runs no servers and collects nothing.
• No account, no cloud sync, no analytics SDK, no advertising SDK.
• The app does not encrypt the database itself. It relies on the operating system's protection of app data at rest.
• Network use is limited to three optional things: opening YouTube links from the Yoga tab, the operating system's geocoder to pick a food region (only if you grant location), and an Ollama server you configure yourself for local AI summaries.

Full policy: https://brandbuilder.com.np/privacy-policy-for-open-period-cycle-tracker/ (also in PRIVACY_POLICY.md).

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FAQ

Does it work offline? Yes. Every feature runs on the device. Nothing requires a connection.

Do I need an account? No. Open the app and start logging.

What does it cost? Nothing. There is no subscription, premium tier, or in-app purchase.

Can I export my data? Yes. Profile → Backup exports a JSON file you can keep anywhere and restore later.

Where is the source code? Here: https://github.com/onepiece92/openPeriodTracker, under the MIT license.

Is it medical advice? No. The app is a tracking and information tool. Talk to a healthcare professional about anything that concerns you.

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Tech stack

Layer	Technology
Framework	Flutter 3.x, Dart 3.x
State management	provider
Local database	sqflite (SQLite)
Routing	go_router
Prediction	tflite_flutter with a small LSTM model trained by scripts/train_lstm_model.py
Typography	Google Fonts (Playfair Display, Outfit)

Architecture is feature-first: lib/features/<feature>/ holds screens, lib/core/ holds models, providers, database and theme.

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Getting started

Prerequisites: Flutter SDK 3.x, Xcode for iOS or Android Studio for Android.

git clone https://github.com/onepiece92/openPeriodTracker.git
cd openPeriodTracker
flutter pub get

flutter run -d ios      # iOS simulator
flutter run -d android  # Android emulator
flutter run -d chrome   # web

To regenerate the prediction model:

pip install tensorflow numpy
python scripts/train_lstm_model.py

Store metadata lives in fastlane/metadata/. The landing page lives in docs/ and is served by GitHub Pages.

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Contributing

See CONTRIBUTING.md. Contributions must keep the app offline-first and free of tracking. Security concerns: see SECURITY.md.

License

MIT. See LICENSE.