A private period tracker that doesn't sell your data
tadoy's cycle module is a calm menstrual tracker built on the same posture as the rest of the app: your data stays on your device. Period dates, flow, ovulation estimates, symptoms — none of it is synced to our servers, sold to data brokers, or used to train any model. Two-way Apple Health, so your existing history doesn't disappear.
What's in the cycle module
- Period dates & flow — start, end, light/medium/heavy. Two taps.
- Ovulation estimate — based on your actual logged history, not a fixed 28-day assumption.
- Symptom log — cramps, mood, sleep, energy, headache, libido, spotting, and free-text notes.
- Cycle calendar — see this cycle and recent ones on one page, with phases shaded gently.
- Apple Health two-way — reads existing HealthKit entries; writes new ones back.
- Journal pairing — write a note next to any day if it helps to remember context.
- Cycle on the daily page — current phase quietly visible alongside sleep, mood and habits.
Why privacy matters in cycle tracking specifically
Cycle data can imply pregnancy, fertility intent, sexual activity and hormonal conditions, and the last few years have made the stakes of that data leaking very concrete. tadoy's answer is structural — we don't sync cycle data to our servers, so there's no server copy to breach, subpoena, or quietly share. The optional evening review can include "cycle day" as one signal it summarises; it's opt-in.
Privacy
Cycle, symptom and ovulation logs live on your device — not synced to tadoy's servers, not used to train any model. The same on-device posture as journal, mood, body and habits. Full detail on the privacy page.
How tadoy compares to other period trackers
- vs Flo — the largest period tracker by scale; it also settled with the US FTC in 2021 over sharing user data with Facebook and Google, and runs a server-side model. tadoy's answer is "no server copy" — a different posture, not a different policy.
- vs Clue — the credible European-privacy-first option, server-side and GDPR-backed. tadoy overlaps in spirit but is on-device only and a daily page rather than a cycle specialist.
- vs Natural Cycles — the only FDA-cleared cycle-tracking contraceptive app. tadoy is not a contraceptive method — Natural Cycles or a doctor is the right place for that.
- vs Apple Health — Apple's cycle tracking is excellent, free and on-device, and tadoy reads from and writes to it; tadoy's lane is cycle inside a wider editorial daily page.
Reflective, not medical
tadoy's cycle module is a reflective tracker, not a medical device — it doesn't diagnose, doesn't replace clinical advice, and doesn't claim contraceptive accuracy. The estimates are exactly that, based on the history you've logged. For PCOS, perimenopause, fertility planning, contraception or any cycle-related medical concern, talk to a doctor.
See the daily page Read the privacy page
Common questions about cycle tracking
- Do you sell my period data?
- No. We can't — it isn't synced to our servers. It lives on your device.
- How is this different from Flo?
- Flo has a server-side model and a history of data-sharing settlements. tadoy is on-device by structure.
- Can I use it for contraception?
- No. tadoy is not a contraceptive method. Natural Cycles is the FDA-cleared option; a doctor is the better one.
- Does it sync with Apple Health?
- Yes, two ways. Reads existing entries, writes new ones back.
- What if my cycles are irregular?
- The estimate uses your actual logged history. For very irregular cycles, no tracker estimates well — the journal is often more useful than the prediction.
- What happens to my data if I delete the app?
- It's gone — the data lived on the device, uninstalling removes it. No server copy to clean up.