What’s MetricKit?

MetricKit in a new framework, introduced in iOS 13 (WWDC2019), with which it is intended to gather information (metrics) about battery behavior and application performance. For a registered application, reports on the behavior of said application will be received once a day as a general rule.


Battery metrics include, among other parameters:

  • The state of the mobile network.
  • The transfers through the internet.
  • The use of the CPU.
  • The use of the GPU.
  • The energy used to display the application on the screen.
  • The use of device location functions.


From the point of view of performance, metrics are obtained, for example, on:

  • The time it takes for the application to open (launch time).
  • The response of the application with user interaction.
  • The amount of time the application is active.
  • The use of memory and disk.


In order to receive metric reports, we need to add a subscription to MXMetricManager (for example in the AppDelegate class):

class AppDelegate: UIResponder, UIApplicationDelegate, MXMetricManagerSubscriber {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        let shared = MXMetricManager.shared

        return true

    func applicationWillTerminate(_ application: UIApplication) {

    // Receive daily metrics
    func didReceive(_ payloads: [MXMetricPayload]) {
       // Process metrics

The didReceive method receives an array that contains the information of the last 24 hours (and of all that information that could not be received previously).