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
Period tracking is one of the most sensitive personal-data categories in the App Store. Cycle data can imply pregnancy, fertility intent, sexual activity, hormonal conditions and broader health context — 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 data lives on the device you logged it on. The AI surfaces (Ask, Outlook, the optional evening review) only send what you write in the moment, and the evening review is opt-in. Full detail on the privacy page.
How tadoy compares to other period trackers
- vs Flo — Flo is the largest period tracker by scale and has built a meaningful product. It also settled with the US FTC in 2021 over sharing user data with Facebook and Google, and continues to operate a server-side data model. tadoy's structural answer is "no server copy" — a different posture, not a different policy.
- vs Clue — Clue is the credible European-privacy-first option, with GDPR rights, a clinical research arm, and a public stance against US data-sharing requests. tadoy overlaps in spirit; the difference is data location (Clue server-side, encrypted; tadoy on-device only) and bundle (Clue is cycle-specialist; tadoy is a daily page that holds cycle alongside mood, habits, body and journal).
- vs Stardust — Stardust pitched a privacy-first frame in 2022 with end-to-end-encrypted messaging metaphors. Reception has been mixed. tadoy is simpler: no chat, no astrology mash-up, no cycle-specific social layer.
- vs Natural Cycles — Natural Cycles is the only FDA-cleared cycle-tracking contraceptive app, requires daily temperature readings, and is specifically a fertility-planning tool. tadoy is not a contraceptive method and shouldn't be used as one — Natural Cycles or a conversation with a doctor is the right place for that.
- vs Apple Health — Apple's cycle tracking is excellent, free and on-device. tadoy reads from and writes to it. If Apple's cycle view is enough on its own, you don't need anything else; if you want cycle inside a wider editorial daily page, that's tadoy's lane.
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 — estimates based on the history you've logged. For PCOS, endometriosis, perimenopause, fertility planning, contraception, or any cycle-related medical concern, talk to a doctor. tadoy is the place to notice what's happening in your own body alongside the rest of your day — not the place to make medical decisions.
Cycle inside the daily page
Cycle data is most useful when it sits next to mood, sleep, energy and habits — the things that actually shift across a month. tadoy puts the current phase quietly on the daily page, so a low-energy day shows up next to "luteal, day 24, three hours less sleep" instead of in a separate app you have to remember to open and correlate yourself.
Privacy posture, in one paragraph
Cycle entries are on-device. They are not synced to our servers, not shared with advertisers, not sold to data brokers, and not used to train any model. The optional evening review can include "cycle day" as one of the signals it summarises; it is opt-in, and you can leave it off without losing the rest of the cycle module. Account deletion removes the small amount of account data we hold; uninstalling removes the cycle data itself, because that's where it lives.
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.