Type1OS

Privacy Policy

Last updated: August 2026.

Type1OS is an independent, open-source suite of apps for reading glucose values from Dexcom Share across desktop, mobile, watch, car, and web surfaces. This document explains what data Type1OS apps handle, how Dexcom credentials are stored, and how to contact the maintainer about privacy questions.

Independence from Dexcom

Type1OS is not affiliated with, endorsed by, or supported by Dexcom, Inc. It reads data from the unofficial Dexcom Share wire protocol. Official Dexcom apps remain the source of truth for safety-critical decisions.

What we collect

Type1OS apps run primarily on your own devices. In the default single-device configuration, the apps do not send glucose data, credentials, or usage telemetry to Type1OS-operated servers.

The apps do handle:

• Dexcom Share credentials. Your Dexcom username (or account ID) and password are required to log in to Dexcom Share.
• Dexcom session IDs. After login, Dexcom returns a session ID that is used to fetch glucose readings.
• Glucose readings. Values returned by Dexcom Share, which include the reading value, timestamp, and trend arrow.
• Local preferences. Alert thresholds, refresh cadence, and display settings you configure.

How Dexcom credentials are handled

Dexcom credentials are stored on-device using each platform's secure storage:

• iOS / macOS — Keychain.
• Android / Wear OS / Android Auto — encrypted shared preferences.
• Windows — Credential Manager.
• Web PWA — browser storage with in-browser encryption; the PWA does not send credentials to a Type1OS-hosted server.
• Type1OS Bot (Telegram) — credentials and session IDs are encrypted with a Fernet key before being written to the bot's local SQLite database. Operators are expected to provide the encryption key via environment configuration.

Credentials are sent to Dexcom's servers over HTTPS when you log in or when a stored session expires and the app re-authenticates. They are not sent anywhere else.

Dual-phone / MirrorLink configurations

The dual-phone MirrorLink configuration (documented in the MirrorLink repo) uses a Type1OS-managed backend so two phones can share glucose state. In that configuration Dexcom credentials are stored in backend secret storage; the phones authenticate to Type1OS only and never transfer Dexcom credentials device-to-device. See the dual-phone architecture document for the full data model.

Notifications

When the apps show alert notifications on a lock screen, the default is generic text. Glucose values appear only after the device is unlocked, so a quick glance at a locked device does not reveal health data.

Third-party services

Type1OS apps do not include third-party analytics SDKs, ads, or marketing trackers. The marketing site at type1os.com is a static Vite site served via a hosting provider. The hosting provider may receive standard server logs (IP, user agent, requested path); the site itself does not set analytics cookies.

Children

Type1OS is intended for adults and caregivers of people living with diabetes. It is not directed at children under 13 and should not be used for clinical decision-making for any user.

Your choices

You control your data by:

• Logging out of any Type1OS app, which deletes the stored Dexcom session and credentials from that device.
• Uninstalling the app, which removes all local data.
• Rotating your Dexcom password if you suspect credential exposure; Type1OS sessions will expire and can be re-established with the new password.

Security disclosures

Each repository has a SECURITY.md with the current disclosure contact. Start with the SECURITY.md for this site if you are unsure which repo is relevant.

Changes

Material changes to this policy will be noted by updating the "Last updated" date above. Because the apps run mostly on-device, most policy changes only affect how credentials are stored or how notifications behave.

Contact

Questions about this policy can be opened as an issue on GitHub.