What is geofencing service?

Geofencing is a location-based service in which an app or other software uses GPS, RFID, Wi-Fi or cellular data to trigger a pre-programmed action when a mobile device or RFID tag enters or exits a virtual boundary set up around a geographical location, known as a geofence.

The API uses a pay-as-you-go pricing model. After you consume all the initial free requests, the charges are 5.00 USD per 1000 hits . Now, this is where a custom geofence implementation can help you save up some money.