Vellum: Period Tracker

Your cycle stays on your phone. No account, no cloud, no analytics. Face ID lock, local reminders, home-screen widget, export in 6 languages.

Vellum is a quiet, private almanac for your menstrual cycle.

Estimates only — not medical advice, not a contraceptive.

Every period, symptom, mood, sleep hour, basal body temperature, and note stays inside the app on your device, in a local database. Vellum has no sign-in, no accounts, no cloud sync, no analytics SDK, no crash reporter, and no ads. Your cycle data never leaves your device.

If you have been looking for a period tracker that does not phone home, this is that app.

WHAT YOU CAN LOG

• Flow level, symptoms, mood, energy, sleep hours
• Sexual activity, discharge, medications, free-text notes
• Basal body temperature in C or F

WHAT YOU SEE

• Today screen with an animated ring showing the current cycle day and phase
• Month calendar with per-day phase and flow status
• Insights with a BBT chart and a cycle-length chart you can scrub through
• Cycle history for reviewing and correcting past cycles
• Home-screen widget on iOS showing your current cycle day and phase

PREDICTION YOU CAN INSPECT Next period, fertile window, and ovulation are estimated from your own history, with a confidence label so you can tell when there is not enough data yet. Vellum provides cycle predictions for personal reference and is not medical advice or a contraceptive method.

GENTLE, LOCAL REMINDERS Period, fertile-window, ovulation, and daily check-in reminders are scheduled by the app on your device. There is no push server behind them. Turn each on or off individually.

APP LOCK Face ID, Touch ID, or your device passcode can lock the app. The cover comes back up the moment you switch apps, so nothing shows in the multitasking preview.

EXPORT AND IMPORT Save a full JSON backup or a CSV of your logs through the share sheet. Restore a JSON backup and it is validated before it replaces anything. Delete everything with one action when you want to.

SIX LANGUAGES English, Spanish, French, Portuguese, German, and Arabic with full right-to-left layout. Localization is bundled in the app.

WHAT VELLUM DOES NOT DO

• No sign-in, no account
• No cloud backup, no cross-device sync
• No HealthKit read or write
• No advertising, no third-party tracking, no third-party analytics

Vellum is a period tracker, cycle calendar, ovulation and fertility log, PMS diary, and BBT journal in one small local app.