Cycle predictions
Period and cycle predictions calculated entirely on-device from your logged history. No cloud processing.
Private by design
Cyla
A period & cycle tracker that never leaves your phone. No account, no cloud, no servers — predictions, symptoms and Apple Watch temperature, all on-device.
On-device only
Apple Watch temperature
Smart ring
No account
One-time purchase
iPhone & iPad
Your cycle, at a glance
Everything you need in a couple of taps — log the day, read your predictions, and watch the picture get clearer the more you track. Nothing here is sent anywhere.
What it does
A complete cycle tracker — predictions, fertility windows, symptoms and export — built so your most intimate health data stays yours.
Apple Watch temperature
Reads wrist temperature via HealthKit to help confirm ovulation and improve prediction accuracy.
Daily symptom logging
Log symptoms, moods and notes each day. Everything stored locally, encrypted by iOS.
Fertility tracking
Fertility window estimates based on your cycle data and temperature trends. Available in premium.
Data export
Export everything as JSON anytime. Your data is yours — take it with you if you leave.
No account required
No email, no sign-up, no cloud sync. Open the app and start tracking immediately.
Works with your smart ring
Pair an affordable Colmi-family smart ring straight from Cyla — no separate ring app, no account, and nothing ever leaves your phone. Your ring's everyday wellbeing signals and sleep appear on a dedicated Device tab, entirely on-device.
Everyday vitals
Heart rate, blood oxygen, stress and HRV from the ring, shown with day charts and a 7-day trend. On-device only — no cloud, no login.
Sleep, at a glance
A sleep score, the stage breakdown, and a hypnogram you can scrub with your finger, plus a 7-night trend — so you can see how you actually slept.
Temperature, kept separate
The ring's skin temperature is a wellbeing readout only. Your fertility temperature still comes from Apple Watch — we keep the two apart on purpose.
Private by design
Cyla talks to the ring over Bluetooth itself — your most intimate data stays on your device. You can use it alongside PaceGrid on the same phone.
Supported rings
Tested: COLMI R09. Compatible (same family, not individually tested): COLMI R02, R03, R06, R10 and most rings that pair without their own app. Heart rate is confirmed across the family; sleep accuracy varies by model.
How to pair
1 · Charge it
Give the ring a few minutes on its charger so it has power to connect.
2 · Quit the ring's own app
If you used the official ring app, fully close it. You can keep Cyla and PaceGrid paired at the same time — just don't sync in two apps at the same moment.
3 · Turn on Bluetooth
Make sure Bluetooth is on and Cyla is allowed to use it.
4 · Open Smart Ring
In Settings, open the Smart Ring screen and tap Scan with the ring next to your phone.
5 · Tap your ring
Choose your ring from the list to connect. Cyla remembers it for next time.
6 · Wear it
Wear it overnight — sleep syncs automatically when you reopen the app.
Private, not just promised
Most trackers ask for an account before you can log a single day, then sync your most intimate data to a vendor cloud. Cyla doesn't.
- All health data stored locally with iOS encryption.
- No accounts, no cloud, no servers.
- Apple Watch data via HealthKit — on-device only.
- Nothing to subpoena, nothing to breach, nothing to sell.
Who it's for
Cyla is for people who want a private period tracker, a private cycle tracking app, or a Flo alternative that does not begin with an account signup. It is especially relevant if privacy is not an abstract preference for you, but the main reason you are choosing a new health app.
No account-first workflow
You do not need to create an account just to log a cycle. That changes the feel of the product immediately.
On-device privacy story
Designed to keep sensitive cycle data on the device instead of sending it to a vendor-controlled cloud by default.
Apple ecosystem fit
Apple Watch temperature integration makes Cyla especially relevant for iPhone users who already rely on Apple health features.
Export without lock-in
Export support means your data stays portable rather than trapped in one app.
Built for trust
On-deviceAll data stays local, encrypted by iOS.
Apple WatchTemperature integration via HealthKit.
No accountNo sign-up, no cloud, no tracking.
Frequently asked questions
Is Cyla private?
Privacy is the main point: no account requirement, no cloud-first model, and sensitive health data kept on-device.
Does Cyla work with Apple Watch?
Yes. Apple Watch temperature integration is one of the app's core differentiators for iPhone users.
Compare with Flo or Clue?
Read Cyla vs Flo vs Clue for a privacy-focused comparison.