Privacy Policy – Signal Sentinel

Signal Sentinel

Effective: June 2025

Platform: Android

Version: 1.0

Overview

Signal Sentinel monitors connectivity conditions and alerts you when configured signal conditions are found. It does not control device radios, create in-app accounts, or transmit your monitoring history to any server.

This policy describes what data the app accesses, why, and where it goes. There are no surprises.

Data we collect

Data type	Collected	Shared	Purpose
Approximate location	Yes	No	Signal monitoring (voice lane)
Precise location	Yes	No	Fuller cell-tower signal reads (optional)
Background location	Yes	No	Scheduled checks while screen is off
App activity (in-app actions)	Yes	No	On-device history log (30-day auto-prune)
Crash diagnostics	Yes	Crashlytics	Bug detection and app stability
Device / telephony IDs	Yes	No	Reading telephony service state

All collected data is encrypted in transit. Monitoring history, alert-session state, and the billing cache are stored only on your device and are excluded from Android cloud backup and device transfer.

Location access

Signal Sentinel requests location permission exclusively to read cell-tower signal strength from the Android telephony system. Location data is:

→ Never recorded or uploaded to any server
→ Never shared with third parties
→ Stored only in a local, auto-pruning on-device database
→ Accessed in the background only when scheduled monitoring is enabled

Monitoring continues without background location, but scheduled voice checks may be delayed or incomplete without it.

Permissions used

INTERNET

Required for Play Billing, Firebase Crashlytics (when configured), and data-mode connectivity probes. Probes contact clients3.google.com via HTTPS only.
ACCESS_NETWORK_STATE

Prevents connectivity probes from running when Android reports no internet-capable network.
POST_NOTIFICATIONS

Shows alert notifications when a configured signal condition is detected. Required on Android 13 and above.
READ_PHONE_STATE

Reads cellular service state and registration status for voice-lane monitoring.
ACCESS_COARSE_LOCATION

Baseline access required for the voice monitoring lane.
ACCESS_FINE_LOCATION

Enables fuller cell-tower information reads for more detailed signal data.
ACCESS_BACKGROUND_LOCATION

Allows scheduled voice checks to run while the app is in the background or screen is off. You choose this explicitly; monitoring works without it.
BILLING

Required for Google Play Billing. Payment processing is handled entirely by Google.

Third-party services

Google Play Billing

Subscription purchases are processed entirely through Google Play. Signal Sentinel does not receive or store payment card details. Google's privacy policy governs that transaction.

Firebase Crashlytics

Crash reports may be sent to Firebase Crashlytics when a build is configured with a Firebase app config. Crash data may include device model, OS version, and stack traces. It does not include location or monitoring history. Crashlytics is governed by Google's privacy policy.

Connectivity probes

Data-lane checks test internet usability by performing a lightweight DNS lookup and HTTPS request to clients3.google.com/generate_204. No user data is transmitted in this request. The app does not maintain its own backend server.

Data retention & deletion

Monitoring history is stored locally on your device and is automatically pruned after 30 days. There is no account to delete and no server-side data to request removal of. Uninstalling the app removes all locally stored data.

Crash data held by Firebase Crashlytics is subject to Google's data retention policies.

Children's privacy

Signal Sentinel is not directed at children under 13 and does not knowingly collect personal information from children.

Changes to this policy

If this policy changes materially, the effective date above will be updated. Continued use of the app after changes constitutes acceptance of the revised policy.

Contact

Questions about this privacy policy? Use the support page to get in touch.