Your Cycle Keeper — Private Period & Cycle Tracker

⚠️ Beta Version 1.0.0 — Currently in active development. Features may change and bugs may occur.

AES-256-GCM encrypted. Zero data collection. Forever free.

Your Cycle Keeper is a privacy-first period and cycle tracking PWA (Progressive Web App). All data is encrypted locally on your device using AES-256-GCM. Nothing is sent to any server. No accounts. No analytics. No tracking.

Features

• 🔒 End-to-End Encrypted — AES-256-GCM encryption with your personal PIN
• 📱 Progressive Web App — Install like a native app on any device
• 🩸 Flow Tracking — Log flow intensity (light, medium, heavy)
• 🤕 Pain Tracking — Rate pain levels from 1-10 in 0.5 increments
• 😊 Mood Tracking — Track mood (low, neutral, happy)
• 📅 Period Markers — Manually mark period start/end dates
• 📝 Daily Notes — Add custom notes (up to 500 characters)
• 📊 Cycle Predictions — Estimates fertile window, ovulation, and next period
• ⏰ In-App Reminders — Banner notification when your period is approaching
• 📈 Symptom Charts — Visual charts with month/year views and data export (PNG)
• 🎨 Interactive Charts — Filter by period, ovulation, flow, pain, or mood
• 📊 Cycle Statistics — View your cycle history and patterns
• ♿ Fully Accessible — WCAG 2.0 compliant with keyboard navigation
• 🚫 Completely Offline — Works without internet connection
• 💾 Encrypted Backup — Export and restore your data with your PIN

How It Works

Cycle Keeper uses the Calendar Rhythm Method and Standard Days Method to estimate:

• Fertile Window — Days 8 through (cycle length − 11)
• Ovulation Day — Approximately (cycle length − 14) days from period start
• Next Period — Predicted based on your cycle length

⚠️ Important: Cycle Keeper is an educational tool only. It is not medical advice and must not be used as a contraceptive or fertility guarantee. Always consult a healthcare professional for medical decisions.

Privacy & Security

• Zero Data Collection — All data stays on your device
• No Servers — No cloud storage, no accounts, no syncing across devices
• No Analytics — No tracking, no telemetry, no third-party code
• Encrypted Storage — Data encrypted with your PIN before being stored
• Open Source — Auditable code for complete transparency

Installation

Web App (Recommended)

Visit: https://yourcyclekeeper.web.app

Then:

1. Click the menu button (⋮) in your browser
2. Select "Install app" or "Add to Home Screen"
3. Cycle Keeper will work like a native app on your device

Local Development

# Clone the repository
git clone https://github.com/pythonime-lab/yourcyclekeeper.git
cd yourcyclekeeper

# Open in browser (requires HTTP/HTTPS for Service Worker)
# Use a local dev server:
python -m http.server 8000
# or
npx http-server

# Visit: http://localhost:8000

Technical Details

• Version: 1.0.0-beta (in active development)
• Framework: Vanilla JavaScript ES6 modules (zero dependencies)
• Architecture: Modular design with separated concerns (crypto, cycles, validation, storage)
• Storage: IndexedDB (persistent, survives cache clearing)
• Encryption: Web Crypto API (AES-256-GCM)
• Key Derivation: PBKDF2 (250,000 iterations, SHA-256)
• Session Security: 5-minute auto-lock with countdown warning
• Offline Support: Service Worker v3.1.0 + Cache-first strategy
• Accessibility: WCAG 2.0 compliant (keyboard navigation, screen reader support, focus management)
• Browser Support: All modern browsers with Web Crypto API (Chrome, Firefox, Safari, Edge)

Data Structure

Cycle Keeper stores in IndexedDB:

• Last period start date
• Cycle length and period duration
• Daily logs with:
  • Flow intensity (1-3: light, medium, heavy)
  • Pain level (1-10 in 0.5 increments)
  • Mood (0-100: low, neutral, happy)
  • Custom notes (up to 500 characters)
  • Period start/end markers
• Cycle history (tracks pattern changes over time)
• PIN-derived encryption keys (PBKDF2 with random salt)

All encrypted locally with your PIN. Never transmitted. No cloud storage.

Official Releases

Official releases are published only by the original author. Any other distributions, builds, or app store listings are unofficial and not supported.

License

GPL v3 — See LICENSE.txt

Medical Disclaimer

This app provides cycle estimations based on average biological patterns. It is NOT medical advice.

Cycle Keeper estimates your cycle using pattern tracking. Actual timing varies due to:

• Stress
• Illness
• Medications
• Hormonal changes
• Individual biology

Do NOT use as a contraceptive or fertility guarantee. Always consult a qualified healthcare professional.

Accessibility

Your Cycle Keeper follows WCAG 2.0 accessibility standards:

• Keyboard Navigation:
  • Tab/Shift+Tab: Navigate forward/backward through interactive elements
  • Arrow Keys: Navigate calendar dates (complex grid component)
  • Enter/Space: Activate buttons and links
  • Escape: Close modals and return focus
  • Digits 0-9 + Backspace: PIN entry on all screens
• Screen Readers: Semantic HTML with proper ARIA labels and roles
• Focus Management: Visible focus indicators, logical tab order
• Form Controls: Native keyboard support for inputs, selects, and textareas

Standards based on Salesforce Accessibility Guidelines.

Contributing

Found a bug? Have a feature idea? Open an issue on GitHub.

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Made with ❤️ for privacy.