Cycle Tracker - Privacy-First Period & Fertility Tracking

Target Launch: March 2025 Status: Idea (not started)

Problem

Period tracking apps (Flo, Clue) have terrible privacy practices. Post-Roe, this is a genuine safety concern. Users sharing intimate health data with ad networks.

Solution

Local-first cycle tracking. All data stays on device. Optional encrypted sync between user's own devices. No cloud, no ads, no data selling.

Target Users

• Privacy-conscious women tracking cycles
• Women in restrictive legal environments
• Anyone wanting health data to stay private

MVP Scope (March)

• [ ] iOS + Android apps
• [ ] Period tracking (start/end dates)
• [ ] Cycle predictions
• [ ] Symptom logging
• [ ] Fully local storage (no account required)
• [ ] Optional: encrypted device-to-device sync
• [ ] One-time purchase via app stores

Out of Scope (v1)

• Fertility/ovulation advanced features
• Partner sharing
• Health provider export
• Wearable integration
• Web app

Tech Stack

• Mobile: React Native or Flutter (share with flock.spot?)
• Database: SQLite (local only)
• Sync: Optional E2E encrypted (user's own iCloud/Google Drive?)
• Payments: App Store / Play Store (no Stripe needed)

Revenue Model

• One-time purchase: $X (no subscription = privacy signal)
• No freemium (avoids "what's the catch" skepticism)

Key Risks

• Competing with free apps (Flo has 200M+ users)
• App store featuring/discovery
• Trust building (why should they trust us?)
• Feature expectations vs Flo/Clue

Differentiators

• Privacy as THE feature, not an afterthought
• No account required
• Open source core? (builds trust)
• Clear privacy policy (plain English)

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Validation Scores

Criterion	Score	Notes
Competition	/5	Flo/Clue dominant, but privacy scandals
Willingness to Pay	/5
Feasibility	/5	Simpler than flock.spot (no background)
Privacy Angle	/5	Perfect fit - health data + legal concerns
Personal Interest	/5
Total	/25

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Research Needed

• [ ] Competitor deep-dive (Flo, Clue, Stardust, others)
• [ ] Post-Roe privacy concerns coverage
• [ ] Pricing research (what do paid alternatives charge?)
• [ ] App store search volume

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Progress Log

• 2025-01-05: Brief created