Bloom
Open-source period tracking. No ads. No BS. Works offline.
A period tracker that respects you. No ads. No "you might be pregnant or dying — pay us $2.99 to find out." Just clean, helpful cycle tracking — encrypted on your device, no account needed. Or create a cloud account for cross-device sync. Your choice.
Works Offline
Install as an app. Works without internet after first visit. No server needed.
Encrypted on Device
AES-256 encryption with your passphrase. Even we can't read your data.
Period Prediction
Know when your next period is coming, months in advance.
Symptom Tracker
Log symptoms and spot patterns across your cycle.
Partner Access
Share cycle info with your partner so they can be supportive.
Zero Data Collection
No account needed. No tracking. No data selling. Open-source and auditable.
📱 How Local-Only Mode Works
Three steps. Under a minute. Maximum privacy.
- Tap "Use Local-Only Mode" above — no email or signup needed
- Create a passphrase (8+ characters) — this encrypts everything on your device
- Start tracking — periods, symptoms, journal. All encrypted. All offline.
Pro tip: On your phone, tap the browser menu → "Add to Home Screen" to install Bloom as an app. It'll work without internet after that.
🔐 Security Details
- Encryption: AES-256-GCM — the same standard used by banks and governments
- Key derivation: PBKDF2-SHA256, 210,000 iterations — makes brute-force attacks impractical
- Auto-lock: Configurable timeout (2/5/10/30 min) locks data if you step away
- Passphrase change: Re-encrypts all data instantly with your new passphrase
- Zero-knowledge: Server never receives your data or passphrase. Ever.
- Backup: Export encrypted or plain JSON to move between devices
☁️ Want cloud sync later?
Export your data as plain JSON → create a server account → import. You can switch back and forth anytime.