Privacy Policy

1. Controller

2. Purpose and scope

Gauge lets users create personal dashboards and metrics, record values, and evaluate developments. The iOS app can be used without an account. Sign-in is required only for optional Gauge+ synchronization and related online services.

3. Local storage and iCloud

Dashboards, metrics, target ranges, and values are initially stored on the device. If iCloud is enabled for Gauge, this data may be synchronized between devices through the private CloudKit database of the user's personal iCloud account. The controller cannot access this private CloudKit database.

Apple's privacy terms also apply to iCloud and CloudKit. iCloud use can be controlled in the device settings.

4. Optional Gauge+ synchronization

Users may voluntarily connect Gauge to the Gauge backend. Sign in with Apple is used for this purpose. Gauge processes the app-specific user identifier supplied by Apple and, if released, the user's name and email address. Necessary session or access tokens are used for sign-in and are generally limited to no more than 30 days.

Once enabled, dashboards, metrics, descriptions, units, target ranges, aggregation settings, and manually entered values are synchronized with the Gauge backend. After explicit authorization, this allows them to be made available to compatible AI services through the Gauge MCP service. The legal basis is Article 6(1)(b) GDPR (providing the service selected by the user). Article 6(1)(f) GDPR may additionally apply to security and abuse prevention.

Synchronization is disabled by default. Disconnecting deletes the synchronized Gauge+ data from the server. Deletion can also be requested using the email address above.

5. MCP and AI use

When Gauge+ synchronization is enabled, users can connect the Gauge MCP service to a compatible AI service. After explicit authorization, that service may access data stored in the Gauge backend and—depending on the granted permission and specific instruction—read, add, change, or delete data.

The selected AI provider processes the conversation under its own privacy policy and sends information required for tool calls to Gauge. Gauge does not automatically receive the complete conversation. Values imported directly from Apple Health are unavailable to the MCP service because they are not transferred to the Gauge backend.

6. Apple Health

With explicit permission, Gauge can read selected data from Apple Health. The currently supported types are body weight, body fat percentage, resting heart rate, steps, VO₂ max, heart rate variability, exercise minutes, active energy, and walking and running distance. Gauge requests read access only and does not write data to Apple Health.

The initial or manual import may include the previous 90 days. Gauge then refreshes recent data when the app becomes active, at most once every 15 minutes, and performs a longer reconciliation once per day. Health data is not used for advertising, tracking, or marketing and is not transferred to the Gauge backend. Permissions can be changed or revoked in Apple Health at any time.

7. Subscriptions and in-app purchases

Optional subscriptions are purchased through and processed by the Apple App Store. Gauge checks the entitlement status supplied by Apple on the device to unlock subscribed features. Gauge does not collect or store payment information such as card or bank details.

8. Shortcuts, Siri, notifications, and local insights

Gauge provides App Shortcuts and, with permission, can display local notifications. Apple processes information required for Siri, Shortcuts, and notifications according to the device settings.

Insights, trends, and summaries in the iOS app are generated on the device using rules. No data is sent to an AI or analytics service for this purpose. Health-related information is for personal guidance only and is not medical advice or a diagnosis.

9. Website, cookies, and tracking

Gauge contains no advertising and uses no third-party analytics, profiling, or tracking services. For signed-in users, the website uses only technically necessary session cookies. Data is not sold or disclosed for advertising purposes.

10. Recipients and technical providers

Unless web synchronization is enabled, the controller generally does not receive content stored in Gauge. When synchronization is enabled, the controller and technical hosting providers process the data described in section 4. Apple processes data when iCloud, CloudKit, Apple Health, Sign in with Apple, the App Store, Siri, Shortcuts, or notifications are used. See the Apple Privacy Policy for details.

11. Retention and deletion

Local data remains until it is deleted in Gauge or the app and its data are removed. CloudKit data remains in the personal iCloud account until deleted there. Optional Gauge+ synchronization data remains until Gauge+ is disconnected or deletion is requested from the controller. Technical authorization codes are valid only briefly; sessions generally expire after no more than 30 days.

12. Rights

Subject to applicable legal requirements, users have rights including access, rectification, erasure, restriction, data portability, and objection. Users may also lodge a complaint with a competent data protection authority.

Because the controller does not receive content stored locally or in the private iCloud database, rights relating to that data are generally exercised directly in the app or device settings. The email address above can be used for data held by the optional online service.

13. Security

Gauge uses the security mechanisms provided by iOS, HealthKit, iCloud, and CloudKit. Connections to the web service are encrypted in transit, and sign-in is protected by technically necessary tokens. Users should protect their devices with a passcode, Face ID, or Touch ID and keep the operating system up to date.

14. Changes

This Privacy Policy may be updated when features or legal requirements change. The current version will be published at this address.