Privacy Policy
Last updated: November 10, 2026
Biotide ("we", "our", or "the app") is committed to protecting your privacy. This Privacy Policy explains what information we and our service providers handle when you use our iOS application, the biotide.app website, and related services.
The short version: Biotide has no account, no server, no analytics and no advertising in the app. What you enter and what the app reads from Apple Health stays on your device. We never see it.
Information We Collect
Biotide does not require account registration or login.
Stored locally on your device only:
- Your birth date, used to draw your three cycles
- Your daily check-ins: energy, mood, focus and sleep ratings, and an optional note
- The people you add: name, birthday, relation, and a photo if you choose one
- App settings, such as reminder times
This information is kept in the app's private storage on your device. The widgets read your birth date from a storage area shared only between Biotide and its widgets.
Apple Health
If you choose to connect Apple Health (part of Biotide Plus), Biotide reads four types: sleep analysis, heart rate variability, resting heart rate and respiratory rate. Nothing is read until you allow it in the system permission sheet. Biotide compares these values with your own previous 28 days on your device and shows the result in the app.
Biotide never writes to Apple Health, never copies Health data off your device, never stores it in iCloud, and never uses it for advertising or shares it with anyone. You can turn off access at any time in the Health app or in Settings, Privacy & Security, Health.
Contacts
If you allow it, Biotide reads the names, birthdays and photos in your contacts to show everyone with a birthday in People. iOS lets you share all your contacts or only the ones you choose, and you can change that at any time in Settings. What Biotide keeps stays on your device and is never uploaded. You can also add a single person through the system contact picker, which gives Biotide only that contact.
iCloud Sync
iCloud sync is off until you turn it on in the app's Settings, under Data & Sync. When it is on, your birth date, check-ins and the people you added (with any photo you chose for them) are stored in your own private iCloud database through Apple's CloudKit, so your other Apple devices can show them. This sync is operated by Apple, not by us, and is subject to Apple's Privacy Policy. We cannot read your iCloud. Apple Health data, contact photos and your contacts themselves never sync. When you turn sync off, you can choose to delete Biotide's data from iCloud.
Calendar and Notifications
Adding a day to your calendar uses the system calendar editor; Biotide does not read your calendar. Check-in reminders and transition-day notes are scheduled on your device, and you can turn them off in the app or in Settings.
Purchases
Biotide Plus subscriptions and the one-time purchase are handled by Apple through the App Store. We do not receive your payment details, your Apple ID or your name; the app only learns whether Plus is active on your account.
Third-Party Service Providers
Depending on how you use the app and this website, the following third parties may process data:
- Apple — App Store distribution and, if enabled, iCloud sync — Privacy Policy
- Google Analytics — optional website analytics on this site only (not in the app) — Google Privacy Policy
- Cloudflare Web Analytics — cookieless, aggregate page-view counts on this site only (not in the app); it sets no cookies, stores nothing in your browser, and does not identify or track you across sites — Cloudflare Web Analytics
Website Analytics and Consent
This website uses one optional measurement tool, Google Analytics, which tells us how the site is used. Whether it runs before you make a choice depends on where you are:
- European Economic Area: Google Analytics is not loaded until you select “Accept” in the banner.
- United Kingdom: Google Analytics runs from your first page view to produce aggregate statistics that help us improve the site, as UK law permits, with Google Signals and ad personalisation switched off. “Turn off” disables it.
- Switzerland and everywhere else: Google Analytics runs from your first page view, and the banner lets you turn it off.
Your choice is stored in your browser and applies to later visits. We determine the region from your device’s time zone and language settings, treating unclear European cases under the European Economic Area rules, and Google’s Consent Mode additionally applies the European Economic Area default based on your network location. This website does not change its behavior in response to browser Do Not Track signals; use “Cookie Settings” instead.
When it runs, Google Analytics may process the page viewed, referring page, timestamp, browser and device characteristics, screen size, approximate location derived from the network request, and clicks on App Store download links. It does not receive your name, email address, or anything from the app. We do not show ads on this site or in the app.
You can change your choice at any time through “Cookie Settings” in the footer. Turning analytics off after it was running immediately disables future analytics events and reloads the page without the Google Analytics script.
Separately from Google Analytics, this website counts page views with Cloudflare Web Analytics. It runs without the banner because it uses no cookies, stores nothing on your device, and does not build a profile of you: Cloudflare receives the page viewed, the referring page, and coarse browser and country information, and reports them to us only as aggregate totals.
Data We Do Not Collect
- We never receive your name, email, phone number, address, or any other identifying information. The names and birthdays you enter for people stay on your device.
- We do not require account creation or login.
- We do not sell, rent, or trade any data to third parties for advertising or any other purpose.
- We do not use cookies or tracking technologies in the iOS app.
Data Retention and Your Control
All app data is stored locally on your device (and in your own iCloud if you turned on sync). You control it at any time:
- Edit or delete single check-ins and people within the app
- Export everything as JSON, or your check-ins as CSV, in the app's Settings, under Data & Sync
- Delete all data from the app in the same place; with iCloud sync on, this deletes it from iCloud too
- Uninstall the app, which deletes its data on that device
European Users (GDPR)
If you are in the European Economic Area, United Kingdom, or Switzerland, you have the following rights under the General Data Protection Regulation regarding personal data we process about you (limited to the website measurement described above; the app involves no processing by us):
- Right of access — request a copy of the data we hold
- Right to rectification — request correction of inaccurate data
- Right to erasure — request deletion of your data
- Right to restrict or object to processing
- Right to data portability
- Right to lodge a complaint with your national data-protection authority
The legal basis for cookieless aggregate page-view counting with Cloudflare Web Analytics is our legitimate interest in knowing how many people read this site (GDPR Article 6(1)(f)); it involves no cookies or identifiers. In the European Economic Area, the legal basis for Google Analytics is your consent under GDPR Article 6(1)(a), which you can withdraw at any time through Cookie Settings. In the United Kingdom, Switzerland and elsewhere, Google Analytics runs on our legitimate interest in understanding how the site is used so we can improve it, and you can object at any time through Cookie Settings. To exercise any right above, email privacy@biotide.app; we will respond within 30 days.
California Users (CCPA / CPRA)
If you are a California resident, you have the following rights under the California Consumer Privacy Act and California Privacy Rights Act regarding personal information we process:
- Right to know what categories of personal information we collect and how we use them
- Right to delete personal information we hold (subject to legal exceptions)
- Right to correct inaccurate personal information
- Right to opt out of any "sale" or "sharing" of personal information — we do not sell or share personal information, so this opt-out is effectively always active for our users
- Right to non-discrimination for exercising these rights
To exercise these rights, email privacy@biotide.app.
Data Security
Your data stays on your device under iOS's protections. Any traffic from the app or this website is encrypted with HTTPS/TLS. We have no access to your Apple ID or payment details.
Children's Privacy
The app is not directed at children under the age of 13 in the United States, or under the age of 16 in the European Economic Area. We do not knowingly collect information from children below these ages. If you believe we have inadvertently received such information, please contact us and we will delete it.
Changes to This Policy
We may update this Privacy Policy from time to time, particularly as the app evolves. We will post the new Privacy Policy on this page and update the "Last updated" date at the top.
Contact Us
If you have any questions about this Privacy Policy or wish to exercise any rights described above, please email:
For product questions, see our general support address: