Geofencing API with device tracking and dwell-time detection

Enter and exit events answer "did this device cross the boundary." They don't answer the question that actually matters operationally most of the time: is this device behaving the way it's supposed to once it's inside the zone. A delivery rider who enters a drop-off zone and leaves 90 seconds later is a normal delivery. A rider who enters and stays for 40 minutes is either stuck, having a problem, or doing something you'd want to know about.

That's what dwell-time detection is for — and it's a first-class feature in Fencemaker, not something bolted on top of basic enter/exit triggers.

How dwell detection works

You set a dwell threshold per zone — how long is normal, how long triggers an alert. Fencemaker tracks time-in-zone per device and fires a geofence.dwell event once a device crosses that threshold, separate from the enter/exit events you'd already get.

POST https://your-app.com/webhooks/fencemaker
{
  "event": "geofence.dwell",
  "zone_id": "zone_delivery_point_88",
  "device_id": "rider_4471",
  "dwell_seconds": 2400,
  "threshold_seconds": 600,
  "timestamp": "2026-08-18T14:22:00Z"
}

Where dwell detection actually gets used

Delivery and logistics. Flag riders or drivers stalled at a drop-off point well past expected delivery time — often the earliest signal of a problem, well before a customer complaint arrives.

Field service. Confirm a technician actually spent meaningful time on-site rather than just passing through the geofence boundary, useful for both quality assurance and billing accuracy.

Fleet and territory management. Detect vehicles or reps lingering outside their assigned territory, or spending unusually long stretches in a single zone when a route should be moving continuously.

Security and compliance. Flag unauthorized dwelling in restricted zones — a device that shouldn't be stationary somewhere staying there anyway.

What device tracking includes beyond dwell time

Continuous position tracking per device, not just point-in-time checks
Per-zone dwell thresholds, configurable independently for each geofence
Historical dwell data for pattern analysis — which zones consistently see longer-than-expected dwell times
The same webhook delivery (Slack, Telegram, or your own endpoint) as enter/exit events

If your current geofencing setup only tells you when a boundary was crossed and nothing about what happened after, dwell-time detection is the layer that turns a simple trigger into an actual operational signal.