> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getuserkit.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuring the SDK

It is important that you configure the SDK with your **API Key** as soon as the app launches.

### API Key

If you haven't already, [sign up for a free account](https://getuserkit.com/signup) on UserKit. Once logged in, click on your app name in the top left, then click **Settings** and copy your **API Key**:

<img className="rounded-lg" src="https://mintcdn.com/userkit/u7uRrIvdXG8opqR4/images/configure-sdk-step-1.png?fit=max&auto=format&n=u7uRrIvdXG8opqR4&q=85&s=4e9e33505b436defebdf874d3930691f" width="2940" height="1632" data-path="images/configure-sdk-step-1.png" />

### Initialize UserKit

<CodeGroup>
  ```swift Swift-UIKit theme={null}
  // AppDelegate.swift

  import UIKit
  import UserKit

  @main
  final class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(
      _ application: UIApplication,
      didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {
      UserKit.configure(apiKey: "YOUR_API_KEY") // Replace this with your API Key
      return true
    }
  }
  ```

  ```swift SwiftUI theme={null}
  // App.swift

  import SwiftUI
  import UserKit

  @main
  struct MyApp: App {
    init() {
      UserKit.configure(apiKey: "YOUR_API_KEY") // Replace this with your API Key
    }

    var body: some Scene {
      WindowGroup {
        ContentView()
      }
    }
  }
  ```

  ```objc Objective-C theme={null}
  // AppDelegate.m

  #import "AppDelegate.h"
  #import <UserKit/UserKit.h>

  @implementation AppDelegate

  - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
      [UserKit configureWithApiKey:@"YOUR_API_KEY"]; // Replace this with your API Key
      return YES;
  }

  @end
  ```
</CodeGroup>

This configures a shared instance of `UserKit`, the primary class for interacting with the SDK's API. Make sure to replace `YOUR_API_KEY` with your API key that you just retrieved.

<Check><strong>Nicely done!</strong> The last thing to do now is identify your users then you are ready to make calls.</Check>