Geofencing
Drawing a virtual boundary around a real-world location so an app can react, for example with a push notification, when a user's device enters, leaves or stays inside it.
Definition
Geofencing is a location technique where an app defines a virtual perimeter, a geofence, around a point such as a store, airport or stadium, usually as a center coordinate and a radius. The phone's operating system watches for the device crossing that boundary and tells the app when it enters, exits or dwells inside the area. In marketing, geofencing triggers messages tied to place: a welcome offer when someone walks into a store, a reminder to check in near the airport, or a survey after a visit.
Why It Matters
Location is one of the strongest signals of intent: someone standing outside your shop is closer to buying than someone reading your newsletter on the couch. Geofencing turns that moment into a message without the user opening your app. It also has real costs. It needs "Always" location permission, which many users refuse, it can drain trust if messages feel like surveillance, and operating systems cap how many regions an app can watch. Used sparingly, for places users care about, it is one of the highest-converting mobile triggers.
How It Works
The app registers geofences with the operating system through Core Location on iOS or the Geofencing API on Android. Each platform limits how many regions one app can monitor at once, 20 on iOS and 100 on Android, so apps with many locations register only the nearest ones and refresh the set as the user moves. When the device crosses a boundary, the OS wakes the app, which reports an enter or exit event to the backend. Dwell is measured as time spent inside after entering. The backend then decides whether to send a push, show an in-app message or start an automation, usually with a cooldown so the same person is not messaged every time they pass by.
Example
A grocery chain with 400 stores sets 150-meter geofences around each one:
- Enter: No message, just record the visit.
- Dwell for 10 minutes: Push "Don't forget your weekly coupon. Tap to show it at checkout." at most once a week.
- Exit after a visit with no purchase: Add the user to a "visited, did not buy" segment for an email the next day.
Best Practices
- 1Ask for location permission only after explaining what users get in return
- 2Use a radius of at least 100 to 150 meters, since smaller fences are unreliable
- 3Prefer dwell over enter for marketing messages to avoid triggers from people passing by
- 4Add cooldowns and frequency limits so no one gets a message on every visit
- 5Never send location-based messages that reveal sensitive places or habits
- 6Measure lift with a holdout group, since many geofenced visitors would have bought anyway
Geofences that start journeys
Sequenzy's mobile SDKs report enter, exit and dwell events for up to 10,000 geofences per workspace, so a visit can trigger push, in-app messages or email from a sequence.
Learn MoreGeofence Event Types
| Event | Fires when | Good for |
|---|---|---|
| Enter | The device crosses into the area | Logging visits, arrival check-ins |
| Dwell | The device stays inside for a set time; Android supports this natively | Offers and reminders with real intent |
| Exit | The device leaves the area | Feedback requests, follow-ups |
iOS region monitoring reports entry and exit; a dwell workflow needs additional application logic.
Platform Region Limits
| Platform | Regions per app | Permission for background events |
|---|---|---|
| iOS | 20 | Always location access |
| Android | 100 per device user | Background location access |