Sync - Private Period Tracker

Track your cycle privately, understand patterns, and share only the timing and support context you choose with a trusted partner.

Sync Period is a local-first cycle tracker built for simple daily use and private partner support.

Log periods, symptoms, moods, and notes; view your calendar and pattern summaries; set reminder. Your cycle history is encrypted on your device.

Private predictions adapt to your recent cycle history and confirmed corrections entirely on your device. Sync shows an honest likely-start window and confidence level, learns recurring pre-period patterns, and can use an enabled BBT signal or positive ovulation test without uploading those health details. Predictions become more cautious when history is sparse or variable.

Partner sharing is optional and off by default. You choose which supported cycle details to share. Updates are end-to-end encrypted and require the complete private invite to open. Each encrypted relay update expires after no more than 30 days; active sharing renews that rolling expiration when a new update is published. Recent physical symptoms and flow, sex-drive and intimacy check-ins, and moods are three separate opt-ins that can each be turned off again. Intimate sharing is off by default and never indicates consent. Discharge, medications, written notes, and other sexual details remain private.

Sync Period has no ads, no behavioral analytics SDKs, and no required account. You can export a private backup or permanently delete local app data at any time.

Cycle predictions and pattern summaries are estimates. Sync Period does not provide diagnosis, contraception, or medical advice.