Hello I am trying to to track phone data usage (both Wi-Fi and Cellular). I am using the following code to get device data usage https://stackoverflow.com/questions/25888272/track-cellular-data-usage-using-swift as I understand it is the only way to get it without having to use private API's. The problem is I can't figure out why the usage seems to be high compared to other apps that track data usage. I was wondering if anyone could provide documentation on the interfaces used on the code from stack overflow or how to get access to more detailed data usage. What I am doing with the code from stack overflow is take the total Wi-Fi and cellular usage and compare it with the new one every 15 minutes to store a data usage event. public func calculateTempDataUsageEvent() -> Void { let totalWifiDataUsage = Int64(wifiNetworkInfo.getWifiDataUsage()) let totalCellularDataUsage = Int64(cellularNetworkInfo.getCellularDataUsage()) let firstTimestamp = Date().millisecondsSince1970 let tempDataUsageEvent : TempDataUsageEvent let phoneDataUsage : PhoneDataUsage let realm = try! Realm() //Check if realm for PhoneDataUsage is empty, if this is the case store initial phone data usage so we can keep track of it's changes if(realm.objects(PhoneDataUsage.self).isEmpty) { phoneDataUsage = PhoneDataUsage(timestamp: firstTimestamp, offsetMinutes: Int32(TimeZone.current.secondsFromGMT() * 1000), totalCellularDataUsage: totalCellularDataUsage, totalWifiDataUsage: totalWifiDataUsage) do { try realm.write { realm.add(phoneDataUsage) print("Stored Phone Data Usage in Realm") } } catch let error as NSError { print("Failed to store Phone Data Usage in Realm with \(error)") } return } else { //TODO: Handle this unwrap in a better way let lastPhoneDataUsage : PhoneDataUsage = getLastPhoneDataUsage()! let tempEndTimestamp : Int64 = Date().millisecondsSince1970 let tempEventDuration : Int32 = Int32(tempEndTimestamp - lastPhoneDataUsage.timestamp) let tempOffsetMinutes : Int32 = Int32(TimeZone.current.secondsFromGMT() * 1000) //Handle phone restart //TODO: maybe need to know phone uptime possible issue time zone change? https://developer.apple.com/forums/thread/101874 var tempEventWifiDataUsage : Int64 var tempEventCellularDataUsage : Int64 if(totalWifiDataUsage < lastPhoneDataUsage.totalWifiDataUsage || totalCellularDataUsage < lastPhoneDataUsage.totalCellularDataUsage) { if(totalWifiDataUsage < lastPhoneDataUsage.totalWifiDataUsage) { tempEventWifiDataUsage = totalWifiDataUsage } else { tempEventWifiDataUsage = totalWifiDataUsage - lastPhoneDataUsage.totalWifiDataUsage } if(totalCellularDataUsage < lastPhoneDataUsage.totalCellularDataUsage) { tempEventCellularDataUsage = totalCellularDataUsage } else { tempEventCellularDataUsage = totalCellularDataUsage - lastPhoneDataUsage.totalCellularDataUsage } phoneDataUsage = PhoneDataUsage(timestamp: tempEndTimestamp, offsetMinutes: tempOffsetMinutes, totalCellularDataUsage: totalCellularDataUsage, totalWifiDataUsage: totalWifiDataUsage) tempDataUsageEvent = TempDataUsageEvent(startTimestamp: lastPhoneDataUsage.timestamp, endTimestamp: tempEndTimestamp, offsetMinutes: tempOffsetMinutes, eventDuration: tempEventDuration, eventCellularDataUsage: tempEventCellularDataUsage, eventWifiDataUsage: tempEventWifiDataUsage, sendToBackend: true) } else { //Default case where phone has not rebooted and API not reset tempEventWifiDataUsage = totalWifiDataUsage - lastPhoneDataUsage.totalWifiDataUsage tempEventCellularDataUsage = totalCellularDataUsage - lastPhoneDataUsage.totalCellularDataUsage phoneDataUsage = PhoneDataUsage(timestamp: tempEndTimestamp, offsetMinutes: tempOffsetMinutes, totalCellularDataUsage: totalCellularDataUsage, totalWifiDataUsage: totalWifiDataUsage) tempDataUsageEvent = TempDataUsageEvent(startTimestamp: lastPhoneDataUsage.timestamp, endTimestamp: tempEndTimestamp, offsetMinutes: tempOffsetMinutes, eventDuration: tempEventDuration, eventCellularDataUsage: tempEventCellularDataUsage, eventWifiDataUsage: tempEventWifiDataUsage, sendToBackend: true) } } //Write to Realm do { try realm.write { realm.add(tempDataUsageEvent) realm.add(phoneDataUsage) print("Stored Temp Data Usage event in Realm") } } catch let error as NSError { print("Failed to store Temp Data Usage event in Realm with \(error)") } I called temporal data usage as I then use a 'legacy' table to store all usage and temporal data usage is deleted. I do this to know what is not on backend. Finally I add the values from the events and sum them to show data usage. public func getTempDataUsageEventSum() -> (wifiDataUsageSum : Int64, cellularDataUsageSum: Int64) { /** Returns Wi-Fi/Cell total data usage from TempDataUsageEvent Realm, 0 if empty */ let realm = try! Realm() let totalTempWifiDataUsage: Int64 = realm.objects(TempDataUsageEvent.self).sum(ofProperty: "eventWifiDataUsage") let totalTempCellularDataUsage : Int64 = realm.objects(TempDataUsageEvent.self).sum(ofProperty: "eventCellularDataUsage") return (totalTempWifiDataUsage, totalTempCellularDataUsage) }