Privacy Policy

May 3, 2026 · View on GitHub

Red Grid Link Last updated: May 2026

Red Grid Link is built on a simple principle: your operational 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 does not collect personal data, does not run analytics, has no advertising networks, requires no account, and never transmits your operational data (positions, markers, sessions, tracks) to any server.

The only optional outbound data is opt-in crash diagnostics, described below under Crash Diagnostics, which can be disabled by your IT/admin or omitted entirely from a build by your provider.

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:

Calculate and display your current MGRS coordinates on the map
Share your position with nearby teammates during an active Field Link session

Location data is never sent to any server controlled by Red Grid Link or any third party
Location data is stored locally only in the active session database (Drift/SQLite)
Position data persists locally as part of session history, saved tracks, markers, and After-Action Reports until you delete the session
Background location is used only during active Field Link sessions and can be disabled at any time
Crash diagnostics (if enabled in the build) explicitly strip location coordinates from any captured exception payload before transmission

Field Link (Proximity Sync) Data

Field Link uses Bluetooth Low Energy (BLE) to sync position, marker, and annotation data between nearby devices. On iOS, Apple Multipeer Connectivity (which uses AWDL) runs in parallel as a higher-bandwidth secondary transport so peers stay discoverable when the app is backgrounded. On Android, Google Play Services Nearby Connections runs in parallel where Play Services is available; on devices without Play Services the stack falls back to BLE-only.

Field Link communication is end-to-end between paired devices — no data passes through any server or relay
In PIN and QR session modes, Field Link payloads are encrypted with AES-256-GCM using session keys derived from an ECDH P-256 key exchange between paired peers
In Open session mode (auto-join, no PIN/QR), payloads are not encrypted; this mode is intended for training, demos, and trusted environments only
Session keys are derived per session and rotated when the session restarts
Data is exchanged only between authenticated devices in the active session

What Field Link persists locally

These items are saved on your device for as long as you keep them:

The session record (id, name, security mode, operational mode, created timestamp)
Your peers' device IDs, callsigns, roles, and last-known positions
Markers, annotations, and tracks created during the session
After-Action Reports you generate from a session

What Field Link does NOT persist

Ephemeral keys (ECDH session secrets) are held in memory only and discarded when the session ends
Ghost markers (last-known positions of disconnected teammates that haven't been promoted to saved markers) are held in memory only and cleared on session end

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 the tile server you select (OpenStreetMap or OpenTopoMap by default) to download offline region packs. These are standard web requests with no authentication, cookies, or tracking. Public OpenStreetMap tile downloads are subject to that project's Tile Usage Policy; for sustained heavy offline usage we recommend a licensed provider.
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.
Crash diagnostics (optional, release-only): If the build was compiled with a Sentry DSN supplied by your provider, uncaught exceptions and stack traces may be transmitted to Sentry to help us fix crashes. See Crash Diagnostics below.

There is no:

Analytics or usage tracking
Advertising network
Account system or cloud sync of operational data
Telemetry or update check

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

Crash Diagnostics

Red Grid Link uses Sentry for optional crash and exception reporting in release builds only, and only when a Sentry DSN was compiled into the build by the provider. The integration is configured to:

Send false for sendDefaultPii so user-identifying request data is not transmitted
Strip GPS coordinates from captured exception payloads before transmission via a beforeSend hook
Sample 20% of trace events (not user-identifying)
Operate exclusively in release mode — debug and profile builds never initialize Sentry

Crash diagnostics are not enabled in builds without a configured DSN. If you want to verify whether your build has Sentry enabled, see Settings → Help & Support for the build configuration display.

To opt out: use a build that was compiled without a Sentry DSN. Direct downloads from the App Store and Play Store currently include Sentry; enterprise/source builds are at your provider's discretion.

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)	Required to scan for BLE peers and to use Google Play Services Nearby Connections as a parallel transport	Active sessions only
Local Network (iOS)	Field Link peer discovery via Multipeer Connectivity	Active sessions only
Wi-Fi (iOS)	Multipeer Connectivity uses Wi-Fi for high-bandwidth peer transport when available	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's third-party software components:

Sentry — Optional crash diagnostics in release builds only, when a DSN is compiled in. PII off, location stripped, opt-out via a Sentry-less build.
Apple StoreKit / Google Play Billing — Native in-app purchase APIs. Red Grid Link never sees your payment details.
pointycastle — Open-source Dart cryptography library (no data collection).
OpenStreetMap / OpenTopoMap tile servers — Receive standard HTTPS tile requests when you download an offline region pack. URL path only; no cookies, tokens, or identifying information.

The app is built on the Flutter framework.

Children

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

Data Retention

Operational session data (markers, annotations, tracks, peers): Stored locally until you delete the session
Ephemeral session secrets (encryption keys): In-memory only, discarded on session end
Ghost markers (in-memory): Discarded on session end
Map tiles: Cached locally until you delete them
After-Action Reports: Stored locally until you delete them
Preferences: Stored locally until the app is uninstalled
Crash diagnostics (when enabled): Subject to Sentry's data retention policy — typically 30 to 90 days depending on plan

No operational data is retained on any server because no operational 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