The Geofencing API by the World Wide Web Consortium is a type of geolocating API. Geofencing API allows apps to create geographic boundaries around a specific location, and then receive notifications when a device leaves or enters the designated area. This differs from the W3C's Geolocating API in that it can be more power efficient by receiving notifications when a boundary is breached, rather than needing to be continuously checked or refreshed. The Geofencing API can also receive notifications even after the app has been closed. Developers should note that this document is a work in progress and may change. See the project page for a detailed description of current issues and methods.