Mētra

Mētra is a menstrual cycle diary. Private. Local. Yours. Health apps routinely monetize your most intimate data. Mētra doesn't. Every entry lives on your device, encrypted. No server ever sees your data in plaintext. No algorithm learns from your body to serve someone else's interests. **What Mētra does** It helps you understand your own rhythm. Log cycle start and end, flow intensity, physical symptoms, pain. The monthly calendar shows your patterns clearly, without noise. Statistics give back what you observed, without interpreting it for you, without comparing you to a norm. The prediction is honest: it doesn't give you the exact day, it shows you a three-to-five day window, calculated from your personal history, weighted toward your most recent cycles. Because your body is not a machine, and a tool that pretends otherwise is lying to you in a way that costs you trust in yourself. **Privacy is not a setting. It's the architecture.** • All data stays on your device • Database encrypted with AES-256 (SQLCipher) • No Mētra account. No Mētra server. No sign-up required • Optional cloud backup, end-to-end encrypted before leaving your device • The cloud provider (Dropbox) sees only an opaque blob it cannot read • Zero telemetry. Zero analytics. Zero tracking • No data shared with third parties. Ever. **Not a fertility tracker** Mētra does not assume a 28-day cycle. It does not presuppose a desire for pregnancy. It does not send motivational nudges. It does not award badges or streak rewards. It has no gamification. It has no business model that depends on your attention or your data. It is a tool that does what it says, and nothing else. **Open source** The code is public, GPL-3.0 license. Anyone can verify that Mētra does what it promises. Anyone can fork it, as long as they keep it open. Transparency isn't a feature. It's how accountability works. **What's in the app** → Monthly calendar with cycle and symptom visualization → Daily log: flow, pain, physical symptoms, free notes → Next cycle prediction (honest probability window) → Statistics: average duration, variability, full history → Encrypted backup to Dropbox → CSV export of your data → Light and dark theme → Italian and English Mētra is free. No premium tier. No ads. No in-app purchases. The name comes from Ancient Greek: *mētra* (μήτρα) — uterus, but also measure, matrix, meter. The idea that the body has its own rhythm, its own measure, its own time. We chose that name because the name is the promise.