NoctO₂ Privacy Policy

Effective date: 8 November 2026

In short: NoctO₂ keeps your readings on your iPhone. It has no accounts, no analytics, no advertising and no tracking. Nothing leaves your phone unless you set up family alerts: then unanswered alerts, and live readings if you choose to share them, go to your family members through our small relay service. We never sell your data or use it for advertising.

About the app

NoctO₂ connects to your own Bluetooth pulse oximeter to show SpO₂ (blood oxygen) and pulse readings, alert you based on limits you set, and keep a history of your readings. It can also, if you choose, alert family members when an alarm is not answered. This policy explains what information the app handles and what happens to it.

Information the app stores on your phone

Readings from your oximeter: SpO₂, pulse, perfusion index, motion and sensor status, with the time of each reading.
Recordings you download from the oximeter, and summaries made from them.
Alert history: when alerts went off and when you tapped “I’m OK”.
Device details: the name, model and serial number of oximeters you link.
Your settings, such as alert limits and how long to keep readings.

All of this is saved only in the app’s own storage on your iPhone. None of it is sent to us.

Information we do not collect

We do not collect your email address, location, contacts, usage statistics or crash reports. There are no accounts. The app contains no third-party analytics, advertising or tracking code. If you use family alerts, only the limited information described under “Family alerts” is handled by our relay.

Bluetooth

Bluetooth is used only to communicate with your own pulse oximeter: to read its live values and stored recordings, and to change its settings when you ask. The app does not use Bluetooth to find your location.

Notifications

Your own alerts are created on your iPhone by the app itself and are not sent through any server.

Family alerts (optional)

Family alerts are off unless you set them up in the Family tab.

When an alarm is not answered with “I’m OK” in time, the alert (for example “Low SpO₂ 86%”, the family name you chose and the time) is sent through our relay service to your family members’ iPhones, using Expo’s and Apple’s push notification services.

The relay stores only: the family name and the nicknames members choose; push addresses for the phones in the family; join codes; and a 7-day list of family messages (type, alarm name, time, how many phones it reached, and who tapped “Seen it”). Alerts are forwarded without keeping your readings.

If you turn on “Share live readings”, your latest SpO₂, pulse, device and phone battery, and the last hour of readings, are kept on the relay so family members can see them. Older points are deleted automatically.

To slow down code guessing, the relay keeps a salted, one-way hash of the network address of anyone trying to join, for one hour. It cannot be turned back into the address.

The relay runs on Cloudflare. Deleting your family, removing a member, or leaving a family deletes those entries from the relay. Family information is never used for advertising, tracking or any other purpose.

Sharing

Apart from family alerts, your information leaves your phone only if you choose to share it yourself, for example the troubleshooting log from Settings → Diagnostics. In that case it goes only to the app or person you pick in the iPhone share sheet.

Keeping and deleting your data

Live readings and alert history on your phone are deleted automatically after the period you choose in Settings → Storage. You can delete recordings and sessions at any time in the History tab. Deleting the app removes all of its data from your iPhone. If your iPhone backs up to iCloud or a computer, the app’s data may be included in that backup, which is controlled by Apple and you, not by us.

Health information

NoctO₂ is not a medical device and does not diagnose or treat any condition. Your readings are never sold or shared with doctors, insurers, employers or advertisers. They reach family members only if you set up family alerts.

This website

The NoctO₂ website uses no cookies, no advertising and no tracking. It is hosted on Cloudflare, which processes basic technical information (such as your IP address) to deliver and protect the site.

If you use the contact form, we receive your message, the topic you chose and, only if you enter them, your oximeter model and your email address. They are stored on our relay service on Cloudflare, used only to improve NoctO₂ and to reply to you, and deleted within 12 months. To slow down spam, the relay keeps a salted, one-way hash of the sender’s network address for one hour. If you email us, your message stays in our mailbox; ask us any time to delete it.

Children

The app is not directed at children and does not knowingly collect personal information from children.

Changes to this policy

If this policy changes, the updated version will be posted on this page with a new effective date.

Contact

Questions about this policy: ngc1348@gmail.com