---
title: Instrument your watchOS project with New Relic
source: https://docs.newrelic.com/docs/mobile-monitoring/new-relic-mobile-ios/watchOS/instrument-watchos
---

This doc walks you through how to update your watchOS project so you can monitor with New Relic. Because watchOS projects don't already contain an `ApplicationDelegate` or `ExtensionDelegate` class, you'll need to add one or the other to your project. These delegates are necessary to configure and start the New Relic agent in a watchOS project.

## Requirements [#watchos-reqs]

Before adding the `WatchAppDelegate`, first install the [New Relic agent](https://docs.newrelic.com/docs/mobile-monitoring/new-relic-mobile-ios/installation/spm-installation).

> #### ⚠️ IMPORTANT
>
> To ensure proper instrumentation, you must configure and start the agent as the first step in `applicationDidFinishLaunching()` and then run the agent on the main thread. Starting the call later, on a background thread or asynchronously, can cause unexpected or unstable behavior.

After you've installed the agent, see the instructions below for using either [`WatchAppDelegate`](#add-watchappdelegate) or the [watchOs extension](#watchOS-extension).

## Enable New Relic with `WatchAppDelegate` [#add-watchappdelegate]

1.  Create a `WatchAppDelegate.swift` file in your project, then add a class named `WatchAppDelegate` that inherits from `NSObject`. This class should conform to the `WKApplicationDelegate` protocol.
2.  Add the `applicationDidFinishLaunching` to the `WatchAppDelegate` class. As close to the start of the `applicationDidFinishLaunching` function, add `NewRelic.start(withApplicationToken: "APP_TOKEN")`. Be sure to replace `APP_TOKEN` with your[application token](https://docs.newrelic.com/docs/mobile-apps/viewing-your-application-token). Your code might look like this:

    ```swift
    import WatchKit
    import NewRelic
        
    class WatchAppDelegate: NSObject, WKApplicationDelegate {
        func applicationDidFinishLaunching() {
            NewRelic.start(withApplicationToken: "APP_TOKEN")
            return true
        }
    }
    ```
3.  In the main app structure object, add the following snippet:

    ```swift
    import NewRelic

    @main
    struct Watch_App: App {
        @WKApplicationDelegateAdaptor var appDelegate: WatchAppDelegate
    }
    ```

## Enable New Relic with watchOS extension [#watchOS-extension]

1.  Add the `WKExtensionDelegateClassName` key in your WatchKit extension’s `Info.plist` file. This automatically creates a delegate object named `ExtensionDelegate`. For more information, see [WKExtensionDelegate](https://developer.apple.com/documentation/watchkit/wkextensiondelegate).
2.  In the `ExtensionDelegate` class you created, add the `applicationDidFinishLaunching` function.
3.  As close to the start of `applicationDidFinishLaunching` as possible, add `NewRelic.start(withApplicationToken: "APP_TOKEN")` replacing `APP_TOKEN` with your [application token](https://docs.newrelic.com/docs/mobile-apps/viewing-your-application-token). Your code might look like this:

    ```swift
    import WatckKit
    import NewRelic
        
    class ExtensionDelegate: NSObject, WKExtensionDelegate {
        func applicationDidFinishLaunching() {
            NewRelic.start(withApplicationToken: "APP_TOKEN")
            return true
        }
    }
    ```

## Limitations to the watchOS platform [#ios-limitations]

Apple doesn't provide the same iOS APIs to the watchOS platform. This means that certain iOS agent features are not yet available on watchOS. We seek to have parity in our platforms, so as Apple releases new functionality, we will continue to update the agent. Here are some known, currently unsupported features:

-   Crash handling: `PLCrashReporter` is a third party library that the agent uses, which is not compatible with watchOS.
-   Crash count: Because crashes are not reported on watchOS, we can't collect crash count.
-   Handled exceptions: The agent captures and uploads handled exceptions, but New Relic can't currently display them.
-   Background harvesting: If `NRFeatureFlag_BackgroundReporting` is enabled, the agent will continue to monitor the application, but won't harvest or upload to New Relic while in background.
-   Offline marked events: If `NRFeatureFlag_OfflineStorage` is enabled, the agent can store offline harvests and then send them when it's online. Events created in an offline state, however, won't be marked as such on the attribute level.
-   Hot/Cold app start times: The agent depends on UIKit notifications to capture hot/cold start times, but this information is not yet available for watchOS.

If you need additional help, you can reach support at [support.newrelic.com](https://support.newrelic.com).