Notifications & Anti-Tampering
Fami Hero relies on a combination of real-time push notifications, a server-side disconnect watchdog, and local on-device protections to keep parents updated and prevent children from bypassing safety rules. This guide outlines how these notifications work, what happens when a child leaves a Safe Zone, how we prevent tampering, and what actions are automated.
π² 1. Push Notification Catalogβ
Fami Hero dispatches push notifications via Firebase Cloud Messaging (FCM). Parents can customize their alerts under Settings β Notification Preferences (including configuring quiet hours).
| Alert Name | Target | Description | Quiet Hours Bypass |
|---|---|---|---|
| SOS Alert | Parent | Critical priority alert triggered when a child presses the SOS panic button. Includes GPS map and address. | Yes (Continuous alarm) |
| Geofence Alert | Parent | Fired when a child enters or leaves a designated Safe Zone. | Optional (If enabled) |
| Safe Search Alert | Parent | Triggered when inappropriate keywords are detected in apps or notification titles. | Optional (If enabled) |
| Device Offline Alert | Parent | Fired when a child's device stops checking in (due to dead battery, power off, uninstall, or loss of core permissions after a period of time). | Yes (Safety critical) |
| Screen Time Request | Parent | Sent when a child requests extra minutes for a locked application. | No |
| Request Approved/Denied | Child | Notifies the child of the parent's response to their screen time request. | No |
| Limit Config Sync | Child | Silent push that updates app block lists and screen time limits in the background. | No (Silent) |
π’ 2. Leaving Safe Zones (Geofencing Alerts)β
Parents are immediately notified when a child enters or exits a configured Safe Zone:
- Detection: The child app monitors location boundaries locally using Android/iOS geofencing APIs.
- Dispatch: The moment a boundary is crossed, the child device reports the transition to the backend.
- Delivery: The parent app immediately receives a push notification, such as:
- βπ΄ Safe Zone Alert: Sarah has left 'Home'β
- βπ’ Safe Zone Alert: Sarah has entered 'School'β
π‘οΈ 3. Tampering, Permission Revocation & Uninstall Protectionsβ
A common question is: Does the parent get notified immediately when a child uninstalls the app or turns off permissions?
Immediate notifications cannot be sent because when a child revokes location/internet permissions, disables accessibility, or uninstalls the app, the operating system kills the app process immediately, preventing it from making network calls.
[!WARNING] Delayed Inactivity Notifications: If the child's app loses critical permissions (like Location "Always", Notification, Accessibility) or is uninstalled, it will stop communicating with the backend. Since the app cannot send a notification at the moment of uninstallation or restriction, our server-side watchdog monitors the child device's regular check-ins. If no check-in is received within a specific time period, the server automatically sends a warning or critical notification to the parent app.
To ensure safety, Fami Hero uses a two-layer protection strategy:
A. The Server-Side Connection Watchdogβ
The child app regularly checks in with the backend server. If the device goes silent (e.g. due to being uninstalled, turned off, losing core permissions, or internet disabled), the parent is alerted at tiered thresholds:
- β οΈ 12 Hours Offline (Warning): The parent receives a notification that the device has been offline for >= 12 hours.
- π¨ 16 Hours Offline (Critical): The parent receives an urgent alert indicating action is required to verify the device's connection status.
B. Local Active Defenses (Android Child)β
The child app implements local anti-tamper shields to prevent children from disabling the software:
- Accessibility Shield: When the child attempts to open settings to uninstall Fami Hero or turn off permissions, the Accessibility Service detects this and immediately redirects the user back to the Home Screen (if Uninstall Prevention is enabled by the parent).
- VPN Lock: If the child revokes the web filtering VPN, the app detects this and instantly restarts the VPN in the background.
βοΈ 4. Automated Actionsβ
Fami Hero performs several automated blocks and synchronization steps:
- Auto-Block on Install: When a child installs a new app, the child app reports the package to the backend. The system automatically adds it to the child's blacklist and applies group time limits if it falls into a restricted category.
- Auto-Lock on Cap Exceeded: The app automatically locks the child out of restricted apps once their daily screen time limit is reached, displaying a blocking screen.
- Auto-Downtime curfew: At scheduled hours (e.g. bedtime), all apps (except emergency ones) are automatically locked.
- Auto-Restart on Reboot: The protection service launches automatically as soon as the phone finishes booting.