---
title: Adding an AppDelegate to your SwiftUI app
source: https://docs.newrelic.com/docs/mobile-monitoring/new-relic-mobile-ios/troubleshoot/swiftui-appdelegate
---

SwiftUI projects do not generate with an AppDelegate file, which is a necessary component to install and configure New Relic functionality with iOS/tvOS applications. To add an AppDelegate to your SwiftUI App, follow the steps detailed here. Before adding the AppDelegate, follow the [outlined procedure](https://docs.newrelic.com/docs/mobile-monitoring/new-relic-mobile-ios/installation/spm-installation) to correctly install the New Relic agent.

1.  Add a new file to your project named `AppDelegate`

2.  Then in that file add a class named `AppDelegate` that inherits from `NSObject` and conforms to the `UIApplicationDelegate` protocol.

3.  In the `AppDelegate` class you created, add the `application:didFinishLaunchingWithOptions` function.

4.  As close to the start of `application:didFinishLaunchingWithOptions` 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).

    > #### ⚠️ IMPORTANT
    >
    > To ensure proper instrumentation, you must call the agent on the first line of `didFinishLaunchingWithOptions()`, and run the agent on the main thread. Starting the call later, on a background thread, or asynchronously can cause unexpected or unstable behavior.

    ```swift
    import UIKit
    import NewRelic

    class AppDelegate: NSObject, UIApplicationDelegate {
        func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
            NewRelic.start(withApplicationToken: "APP_TOKEN")
            return true
        }
    }
    ```

5.  In the main app structure object add the following line: `@UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate`.

    ```swift
    @main
    struct SwiftUI_ExampleApp: App {
        @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    ```

That is all you need to do to add an `AppDelegate.swift` file to your SwiftUI application and start the New Relic iOS agent in the recommended way.