ZoneAlert

Alerts that reach the people inside the zone, and only them.

ZoneAlert is an emergency alert app with zones drawn on a map. Admins draw the zones, a person allowed to send alerts picks a zone, a severity and a message, and the people inside that zone get the alert as a push notification. We built the app and the backend for Eimskip, through FirstlineIT.

Apps

Three phones with the ZoneAlert app: a port map with three alert zones, the Send Alert sheet with severity Critical, and the details of a critical alert with the affected zone — Real app, example data. Map © OpenStreetMap contributors.

Client: ZoneAlert
Sector: Shipping and logistics
Platforms: iOS and Android app, with a .NET backend
Our role: App and backend
Period: 2025–2026

What was the challenge?

An alert about a chemical spill at one quay is noise to everyone at the other end of the port. The alert has to reach the people inside the zone, also when the app is closed, and a critical alert has to be impossible to miss.

Product: Zone-based emergency alerts
Users: Admins · alert senders · recipients
Status: Live on the App Store

What did bon.do build for ZoneAlert?

We built the app in Flutter with Riverpod and the backend in .NET 10 with MongoDB, Redis and Wolverine. Zones are polygons drawn by tapping points on a map. Alerts go out through Firebase Cloud Messaging, and the phone checks against the zone polygon whether the user is inside. Background location keeps that check current. Critical, high and normal alerts are handled differently, and a critical alert sounds a full alarm.

Zones
Admins draw each zone as a polygon on the map, point by point.
Alerts
Zone, severity and message, sent as a push notification and checked against the zone on the phone.
Backend
A .NET 10 API with MongoDB, Redis and Wolverine for users, roles, zones and alert history.

Technology

Flutter
Riverpod
Firebase Cloud Messaging
.NET 10
MongoDB
Redis
Wolverine

How did the project run?

01Draw
Zones on the map
An admin taps the corners of a zone and saves it with a name and a description.
02Send
One zone, one message
The nearest zone is suggested, then severity and message.
03Receive
Only inside the zone
The phone checks its position against the zone, also in the background.
04Acknowledge
A record of every alert
Recipients acknowledge the alert, and the history keeps zone, sender and time.

Inside the product

The zones on the map, with the button for sending an alert. Real app, example data. Map © OpenStreetMap contributors.
Sending an alert from the map: zone, severity and message. Real app, example data. Map © OpenStreetMap contributors.
The nearest zone is picked from the sender’s location. Real app, example data.

Alert history with severity, zone and sender. Real app, example data.
An alert, its zone on the map and the acknowledgement. Real app, example data. Map © OpenStreetMap contributors.
Admins draw a zone point by point. Real app, example data. Map © OpenStreetMap contributors.

What was the result?

ZoneAlert is live on the App Store. Admins draw zones and manage users, senders alert one zone in a few taps, and recipients can see the alert history and acknowledge each alert. The app is in English, Danish and Icelandic.

Severity3Severity levels: critical, high and normal, each handled differently.

Languages3Languages: English, Danish and Icelandic.

App StoreiOSLive on the App Store since February 2026.