The service is part of an open source project to log GSM CellIDs for cellular network service locations worldwide. It provides free, public, noncommercial access to the CellID database, including cell locations. Applications can use the data to geolocate a device by cross-referencing its broadcast data to the location specified in the database.
API methods include uploading data for a cell location, optionally including signal measurement. Methods also support retrieval of information logged for a cell and of a list of cells within a specified area.