Privacy Policy

Last updated: September 24, 2026

Guardian Monitor is an iPhone and Apple Watch application that displays glucose data from a continuous glucose monitoring (CGM) service you already use. This policy explains what happens to your data when you use it.

In short

Guardian Monitor has no user accounts and no database. We do not collect analytics, we do not track you, and we do not show advertising. The application contains no analytics or crash-reporting software of any kind.

Your glucose data is fetched by the application directly from your CGM provider and stays on your own devices. The only case in which any of it passes through a server we operate is described under Live Activities below, and even then it is forwarded immediately and never stored.

Who we are

Guardian Monitor is developed and operated by Kacper Rychliński, Poland. For any question about this policy or about your data, write to kacper.rychlinski@gmail.com.

You do not create an account with us

The application does not require registration and we do not issue accounts. To use Guardian Monitor you need an existing account with one of the supported CGM services — currently Medtronic CareLink or Sibionics — because the application reads your data through that service.

Your CGM service credentials

When you sign in, the credentials you enter are used to authorise with your CGM provider. They are stored in the keychain on your device, which is encrypted by the operating system, and in your private iCloud Keychain so that your iPhone, Apple Watch and widgets can stay signed in without you logging in on each of them separately. For Sibionics, only a cryptographic hash of your password is stored rather than the password itself.

Your credentials are never sent to us and we have no way of reading them. They travel only between your devices and your CGM provider.

Glucose and treatment data

The application requests your glucose readings, and where your provider supplies them also insulin doses and meal entries, directly from the CGM service. That data is kept on your device so that charts, statistics and alarms continue to work, and it is removed when you log out or delete the application.

Which data is available depends on your provider. Sensor-only services such as Sibionics report glucose alone.

Live Activities

If you enable Live Activities, the Lock Screen, Dynamic Island and CarPlay need to be updated by Apple even while the application is not running. Apple only permits this through a push notification, which has to be sent from a server.

For this purpose, and only while the feature is switched on, the application sends two things to a relay server we operate: the anonymous push token that Apple issued for that Live Activity, and a copy of the data currently shown in the application. That copy contains your recent glucose readings and the patient name or nickname as it appears in your CGM service.

The relay forwards this immediately to Apple's push service so that your Lock Screen can be updated. It is not written to a database, not logged, and not used for any other purpose. Our server is located in the European Union. Turning Live Activities off in the application stops this entirely.

Apple Health

If you enable the Apple Health integration, the application writes your glucose readings, insulin doses and carbohydrate entries into Apple HealthKit on your device. This data stays on your device under Apple's control and is never sent to us or to anyone else by the application. Guardian Monitor only writes to Apple Health and never reads anything from it. You can withdraw access at any time in the Health settings on your device.

Nightscout

If you configure Nightscout synchronisation, the application uploads your glucose readings and treatments to the Nightscout server whose address and access token you enter yourself. That server is yours, not ours. We have no access to it and no involvement in what happens to the data once it arrives there.

Apple Watch and widgets

The Apple Watch application, the complications and the home screen widgets display the same data as the iPhone application. It reaches them either directly from your iPhone or, when they fetch on their own, from your CGM provider. It is shared between your own devices and nowhere else.

Subscriptions and payments

The optional subscription is sold through Apple's In-App Purchase system. Apple handles the payment, and we never see your payment details. The application only learns from Apple whether an active subscription exists and when it expires.

What we do not do

We do not collect usage statistics, device identifiers, advertising identifiers or location data. We do not build profiles, we do not sell or rent data to anyone, and we do not share it with advertisers or data brokers. We do not send marketing messages. There are no public areas in the application where other users could see anything about you.

Children

Guardian Monitor is rated 4+ and is frequently used by parents following a child's glucose levels. Because the application has no accounts of its own and collects nothing about its users, it does not knowingly hold any information about children. If you believe otherwise, contact us and we will look into it.

Your rights

Under the General Data Protection Regulation you have the right to access your personal data, correct it, have it erased, restrict or object to its processing, and to lodge a complaint with a supervisory authority — in Poland, the President of the Personal Data Protection Office.

In practice we hold nothing to give you or to delete: there is no account and no stored record of you. To remove the data held on your device, log out of the application or delete it. To remove the data held by your CGM provider, contact that provider directly, since it is their service that holds your medical records.

Changes to this policy

We may update this policy as the application changes. The new version is published on this page together with an updated date at the top. Where a change materially affects how your data is handled, we will also announce it in the application.

Contact

Questions about this policy or about your data: kacper.rychlinski@gmail.com