Last updated: September 21, 2026
BYD Health Monitor consists of two apps.
This App does not collect personally identifiable information such as your name, email, or phone number. Data transmitted to the server is limited to vehicle fault information and push tokens.
The following table describes the data the App handles and where it is stored.
| Data Type | Description | Storage |
|---|---|---|
| Fault Codes | Real-time status of 23 fault codes via BYD HAL API, including severity (CRITICAL/WARNING/INFO). | In-memory only |
| Tire Status | Pressure (kPa), temperature state, and air leak detection for all 4 tires. | In-memory only |
| Battery & Range | Battery percentage, estimated electric driving range, total mileage. | In-memory only |
| Maintenance History | Replacement records entered manually by the user: date, mileage, and optional notes. | Local device DB |
| CRITICAL Alert History | Fault code number, severity, fault name, description, and optional VIN sent to the relay server when a CRITICAL fault is detected. Stored in the server database. | Relay Server DB |
| Push Token (FCM / APNs) | A device-specific token generated when the companion app is installed and paired. Used solely for sending push notifications. | Relay Server DB |
| Pairing Code / vehicle_id | A temporary 6-digit code (valid for 5 minutes) used to pair the vehicle app with the companion app. Invalidated immediately after use. The vehicle_id is an internal UUID. | Device (temporary) |
Real-time vehicle data is discarded when the session ends. Maintenance history is stored only on the vehicle device. Alert history and push tokens are stored on the relay server solely for notification delivery.
Vehicle device (DiLink): Maintenance history is stored exclusively in an SQLite database (Room) on the device. Uninstalling the App deletes this data permanently.
Relay server (Railway.app): CRITICAL alert history and FCM/APNs tokens are stored in a PostgreSQL database hosted on Railway. Tokens are automatically deleted after 90 days of inactivity. All communication with the server uses HTTPS (TLS).
| Permission (App) | Purpose |
|---|---|
| POST_NOTIFICATIONS (Vehicle & Companion) | Displays a notification when a CRITICAL fault is detected. You can disable this in system settings at any time. |
| INTERNET (Vehicle & Companion) | Vehicle App: Sends CRITICAL fault data to the relay server. Companion App: Retrieves alert history and registers push tokens. |
| ACCESS_NETWORK_STATE (Vehicle) | Checks for network connectivity before attempting to send an alert. |
The following third-party services are used to deliver push notifications.
These services do not collect user data for advertising or other purposes beyond notification delivery.
Open-source libraries: Jetpack Compose, Hilt, Room, OkHttp (Apache 2.0) / Flutter, Riverpod, Firebase Flutter SDK (BSD-3)
This App is intended for vehicle operators. We do not knowingly collect any data from children under the age of 13.
This Privacy Policy may be updated as the App evolves. Any changes will be reflected on this page with an updated date and announced via the GitHub repository.