Sync vs Calla

Sync Period tracks cycles locally and supports private sharing with a partner or friend. Log periods, symptoms, moods, and notes; view your calendar and pattern summaries; set optional reminders; and import supported Flo, Clue, Drip, or generic CSV data after reviewing what Sync can recognize. 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 a 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.

Most period apps were built for adults trying to get pregnant. Calla wasn't. It's built for teens who just want to understand what's happening in their body - without the noise, the upsells, or the ovulation countdowns. Your data lives on your phone. No accounts required. No ads. No third parties, no data brokers, no advertisers. Optional parent share, if you want it. Privacy-first. Always. All your data stays on your phone. No accounts. No cloud. No ads. No data selling. Period. Built for how your body actually works Irregular cycles? That's normal, especially when you're starting out. Calla doesn't just assume a 28-day cycle - it learns your patterns and gives you predictions that actually make sense for your body. Track what matters to you Log your period, flow level, mood, energy, cramps, sleep, skin, focus, appetite, and activity. See how your cycle connects to how you feel day to day. Understand your cycle Get gentle, age-appropriate insights about each phase of your cycle - what's happening in your body and what to expect. Prep-day reminders Get a heads-up before your period is predicted to start so you're never caught off guard. Parent Mode Share a simple wellness signal with a parent or guardian - "all good" or "heads up" - without revealing any cycle details. Communication on your terms. Calla is not a medical app. It does not diagnose, treat, or prevent any medical condition. If you have health concerns, talk to a doctor.