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Privacy Policy

Red Grid Link Last updated: March 2026

Red Grid Link is built on a simple principle: your data stays on your device. This policy describes exactly what data the app accesses and what it does with it.

Data Collection Summary

Red Grid Link collects no personal data. There are no accounts, no analytics, no crash reporting, no advertising networks, and no third-party SDKs that collect data. All app functionality works without any server communication.

Location Data

Red Grid Link requests access to your device's GPS location while the app is in use and optionally in the background (for active Field Link sessions). This location data is used solely to:

  1. Calculate and display your current MGRS coordinates on the map
  2. Share your position with nearby teammates during an active Field Link session
  • Location data is never sent to any server
  • Location data is never shared with any third party
  • Location data is stored locally only in the active session database (Drift/SQLite)
  • When a session ends, Field Link position data is discarded unless saved in an After-Action Report
  • Background location is used only during active Field Link sessions and can be disabled at any time

Field Link (Proximity Sync) Data

Field Link uses Bluetooth Low Energy (BLE) and WiFi Direct (Android) / AWDL (iOS) to sync position and marker data between nearby devices.

  • All Field Link communication is encrypted with AES-256-GCM using ECDH P-256 ephemeral session keys
  • Session keys are rotated on every reconnect
  • Data is exchanged only between authenticated devices in the active session
  • Session authentication is user-controlled: Open (auto-join), PIN (4-digit code), or QR code (session key encoded)
  • No data passes through any server or relay -- all communication is direct device-to-device
  • Field Link data is ephemeral -- position and marker sync data is not retained after the session ends
  • Ghost markers (last-known positions of disconnected teammates) are held in local memory only and cleared when the session ends

Stored Data

The following data is saved locally on your device:

All users:

  • Session history (local SQLite database)
  • Downloaded map tiles (MBTiles files, cached locally)
  • App preferences (theme, mode, coordinate format, update interval)
  • Magnetic declination and pace count calibration values

Pro / Pro+Link / Team users:

  • Saved waypoints and markers
  • After-Action Report data (tracks, timestamps, team roster, markers)
  • Display theme and operational mode preferences

All stored data lives on your device only. None of it is ever transmitted to any server.

Network Activity

Red Grid Link makes network requests only for the following purposes:

  • Map tile downloads: Standard HTTPS requests to public tile servers (USGS National Map, OpenTopoMap) to download map packs for offline use. These are standard web requests with no authentication or tracking.
  • In-app purchases: Processed entirely by Apple (App Store) or Google (Play Store). Red Grid Link never sees your payment details and receives no personal data from these transactions.

There is no:

  • Analytics or usage tracking
  • Crash reporting service
  • Advertising network
  • Account system or cloud sync
  • Telemetry or update check

You can verify these claims by monitoring network traffic while using the app.

Permissions

Permission Purpose Scope
Location (While Using App) Display MGRS coordinates, share position via Field Link Foreground
Location (Always) Maintain Field Link sync during background operation Optional, user-enabled
Bluetooth Field Link device discovery and low-power data sync Active sessions only
Nearby Devices (Android) Field Link peer discovery via Nearby Connections API Active sessions only
Local Network (iOS) Field Link peer discovery via Multipeer Connectivity Active sessions only
WiFi High-bandwidth Field Link data transfer (map sync, AAR) Active sessions only
Storage / Files Save downloaded map packs and After-Action Reports Local only
Foreground Service (Android) Maintain Field Link sync when app is in background Active sessions only

No other permissions are requested.

Third Parties

Red Grid Link contains no third-party SDKs that collect data. The app is built on the Flutter framework. In-app purchases use native Apple StoreKit and Google Play Billing APIs -- no third-party purchase SDK is included.

Map tiles are sourced from:

  • USGS National Map (public domain, US government)
  • OpenTopoMap (CC-BY-SA, based on OpenStreetMap)

These tile servers receive standard HTTP requests (URL path only). No cookies, tokens, or identifying information are sent.

Encryption is implemented using the pointycastle Dart library (open-source, no data collection).

Children

This app does not knowingly collect any data from anyone, including children. No account creation is required or possible.

Data Retention

  • Field Link session data: Discarded when the session ends
  • Ghost markers: Held in memory only, cleared on session end
  • Map tiles: Cached locally until the user deletes them
  • After-Action Reports: Stored locally until the user deletes them
  • Preferences: Stored locally until the app is uninstalled

No data is retained on any server because no data is ever sent to any server.

Changes

Any changes to this policy will be reflected in the GitHub repository with an updated date.

Contact

For questions: support@redgridtactical.com GitHub issues: https://github.com/RedGridTactical/RedGridLink/issues