Privacy

Last updated: October 2026

Trace is designed to help you understand patterns and rhythms in your glucose data. Health data should be handled carefully, transparently, and respectfully.

Who we are

Trace is operated by Restless Creative Ltd, a company registered in England and Wales. For privacy matters, contact [email protected].

What Trace stores

Trace may store glucose readings, meal logs, your food library, workout data, sleep data, Daily Reviews, app preferences, notification settings, and optional display name information. Some information is stored locally on your device. Some may be securely transmitted to Trace services to support features such as AI Daily Reviews, notifications, Live Activities, and historical analysis.

The health information Trace keeps on your phone, such as meal analyses, Daily Reviews, workouts and overnight context, is stored on the device itself, not in iCloud. Earlier versions of Trace could keep some of these files in iCloud Drive. Trace now moves them to your device and removes the iCloud copies automatically.

Food library backup

Your food library (foods you add or edit, with their nutrition details, tags and notes) is backed up to your Trace account. This means it can be restored when you reinstall Trace or move to a new phone, and each food keeps the same identity so your meal history continues to match. Your phone keeps its own copy, so the library works without a connection.

If you have saved a meal-timing or insulin approach for a food, such as a pre-meal timing or a split, it is backed up with that food exactly as you saved it. Trace treats it as sensitive account data. The backed-up copy is used only to restore your library. Trace does not change it, and does not use it to make dosing suggestions.

The food library backup does not include any glucose response information. It is deleted when you delete your Trace data.

Personal patterns

To compare new information with your own history, Trace calculates summaries from glucose and contextual data you have already shared with Trace. Examples include how much your glucose varied across a day or night, how long it spent outside your chosen range, how your glucose changed in the hours after a meal you logged, and sleep times where you have shared them through Apple Health. These summaries are kept with your account on Trace’s servers. They are calculated values rather than copies of your glucose readings, and Trace does not collect additional data to produce them. They are used only to understand your own patterns, are never used for advertising, and are deleted when you delete your Trace data.

How glucose data reaches Trace

Trace does not connect directly to your CGM manufacturer. Glucose readings are received from Apple Health (when you grant permission), from a relay service you have independently configured such as Nightscout or Zukka, or through a CGM connection Trace provides directly, such as Libre (LibreLinkUp). Trace reads only the data you explicitly make available through these sources.

If you connect a FreeStyle Libre sensor via LibreLinkUp, Trace uses a narrowly scoped relay service, operated by Hetzner Online GmbH (Falkenstein, Germany), to retrieve your current glucose reading from LibreView. Your LibreLinkUp sign-in credentials are sent to this relay over an encrypted connection so it can do this on Trace's behalf. The relay processes these credentials and glucose data transiently and is not designed to retain them after they are needed to provide the connection. This applies only if you use the Libre/LibreLinkUp connection option; it does not apply to Apple Health, Nightscout, or other connection types.

AI-generated reviews

If AI Daily Reviews are enabled, Trace may send glucose summaries, meal information, workout summaries, and related metabolic context to Trace services for analysis. These reviews are generated automatically and are intended for reflection and pattern awareness only. They are not medical advice.

AI analysis is powered by third-party large language model providers. Trace currently uses OpenAI (GPT-4) and/or Anthropic (Claude) to generate review content. Only anonymised metabolic summaries — not your name or contact details — are sent to these providers. Where Anthropic is used, data submitted through its API may be retained by Anthropic for up to 30 days for safety and security purposes under its standard retention settings. Their processing is governed by their respective data processing agreements.

If you use photo-based meal logging with AI Meal Photo Analysis enabled, the meal photograph itself is also sent to these third-party AI providers to estimate carbohydrates, fat and protein. AI Meal Photo Analysis is off by default and requires your explicit consent in the app, which you can withdraw at any time in Settings.

Lawful basis for processing (UK GDPR)

Trace processes your personal data on the basis of your explicit consent. You provide consent when you complete onboarding and connect your glucose data source. You may withdraw consent at any time by deleting the app and requesting data deletion as described below.

Where Trace processes special category data (health data), the lawful basis is explicit consent under Article 9(2)(a) UK GDPR.

Data retention

Glucose readings, meal logs, and Daily Reviews are retained for as long as your account is active. Personal pattern summaries are kept for up to 14 months; older summaries are deleted automatically. When you delete your Trace data in the app, it is permanently deleted immediately; deletion requested by email is completed within 30 days. Device tokens (used for push notifications and Live Activities) are automatically removed when they expire or when you uninstall the app.

Notifications and Live Activities

If notifications are enabled, Trace may send push notifications relating to glucose alerts, meal analyses, Daily Reviews, and Live Activity updates. Notification tokens are securely registered with Trace services solely to deliver these notifications.

App activity

To understand whether Trace is working as intended, Trace records two simple signals against your random Trace user ID: the dates on which you opened the app, and the first time you open each of three features (Daily Review, Glycemic Flow and Overnight). Each record also includes the app version and build number. These records contain no glucose, meal, workout, sleep or other health data. They are stored on Trace's own servers (Cloudflare), are not shared with any analytics or advertising provider, are not used for advertising, and are not used to track you across other companies' apps or websites. They are deleted when you delete your Trace data.

Data sharing

Trace does not sell personal data. Trace is designed as a personal insight system, not an advertising platform. Your information is not shared with third-party advertisers.

Trace uses the following third-party processors to provide its service: Cloudflare, Inc. (infrastructure and data transit); Hetzner Online GmbH (relay infrastructure for Libre/LibreLinkUp connections only, where enabled); OpenAI, Inc. (AI review generation, where enabled); Anthropic, PBC (AI review generation, where enabled). Each processor is bound by a data processing agreement and is not permitted to use your data for their own purposes.

Where your data is processed

Trace services run on Cloudflare's global network. For users who connect Libre/LibreLinkUp, glucose readings and LibreLinkUp credentials are also processed in Germany by Hetzner Online GmbH, under an Article 28 UK/EU GDPR data processing agreement. AI review generation may involve processing in the United States via OpenAI or Anthropic. Where data is transferred outside the UK, appropriate safeguards are in place in accordance with UK GDPR requirements, including standard contractual clauses.

Your rights

Under UK GDPR you have the right to access, correct, or delete your personal data; to restrict or object to processing; and to data portability. To exercise any of these rights, contact [email protected]. You also have the right to lodge a complaint with the Information Commissioner's Office (ICO) at ico.org.uk.

Data deletion

You can permanently delete your Trace data at any time in the app, from Settings → Delete Trace Data. This immediately deletes your glucose history, meal and food data (including your food library backup), personal pattern and meal response summaries, Daily Reviews, connected CGM credentials and related Trace data from Trace's servers, and clears Trace's data from your device. If you can't access the app, you can request deletion by contacting [email protected]; email requests are processed within 30 days.

Data processing and Apple Health

Health data is processed only with explicit user permission. Trace requests access to Apple Health only when you choose to connect it, and only reads the data types needed to provide the features you enable.

Medical disclaimer

Trace does not provide medical advice. Always consult qualified healthcare professionals regarding medical decisions, treatment adjustments, or health concerns. Features, analysis, and notifications may change over time. Although care is taken to improve reliability and stability, Trace should not be relied upon for medical decision-making.

Contact

For privacy questions or feedback, contact [email protected].