Before starting to add the Sign in with Klarna button or using the Sign in with Klarna SDK you will need to do the following:

1. Implement ASWebAuthenticationPresentationContextProviding
2. Setting the return URL
3. Defining an event handler

The iOS integration will render the sign in flow in a sandboxed in-app browser through Apple's own ASWebAuthenticationSession.

@available(iOS 13.0, *)
extension SignInButtonView: ASWebAuthenticationPresentationContextProviding {
    /// Needed so ASWebAuthenticationSession knows what window to put the view into.
    func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor {
        return window
    }
}

The SDK does all the work on your behalf with the parameters and keys that you supply, but you need to implement support for ASWebAuthenticationContextProviding in one of your classes and forward an instance of it to the SDK.

The UIWindow that your instance supplies will be used to present the in-app browser.

To ensure the Sign in flow initiated by the SDK can correctly redirect back to your application, you must configure a unique return URL (deep link) for your app and provide this URL string to the SDK. This value is required specifically for the Sign in flow initiated by the SDK. Follow our In app guide for setting up the return URL value in your app.

Important: This configuration is distinct from any other return URLs the SDK might require for handling redirects from external third-party applications. Ensure you are configuring the URL for the SDK's Sign in flow.

While the user is interacting with the Sign in with Klarna flow or when the flow is completed, you'll receive events by setting an event handler. You can see a sample event handler on the right.

@available(iOS 13.0, *)
extension SignInViewController: KlarnaEventHandler {
    func klarnaComponent(_ klarnaComponent: KlarnaComponent, dispatchedEvent event: KlarnaProductEvent) {
         if event.action == .klarnaSignInToken {
            // Authorization went through
            let token = event.params["klarnaToken"]
        } else if event.action == .klarnaSignInUserTappedButton {
            // Button was tapped
        } else if event.action == .klarnaSignInUserCancelled {
            // User cancelled out of the flow

Please follow this section if you would like to use one of the button designs provided by Klarna.

You can create an instance of KlarnaSignInButton using its default initializer.

let signInButton = KlarnaSignInButton(clientId: clientID,
                                  scope: scope,
                                  market: market,
                                  locale: locale,
                                  presentationContext: self,
                                  theme: klarnaTheme,
                                  environment: env,
                                  region: reg,
                                  returnUrl: URL(string: "https://sneakers.com")!,
                                  eventHandler: self)

Parameters

When initializing the button, specify the following parameters:

You can add the button to your app's view hierarchy with addSubview(). The button's contents will self-size according to the available space and the user's dynamic type accessibility settings.

When the user taps the button, the sign in flow will be triggered without any additional work from your side. When the flow completes, one of the two methods in your event handler will be called.

When the authentication flow is complete, the klarnaComponent(_:dispatchedEvent:) method of your event handler will be called.

Please follow this section if you want to add a button with a custom design.

​To integrate the Sign in with Klarna SDK in your iOS app, you need to create an instance of KlarnaSignInSDK, call its signIn() function, and receive the results once the flow is completed.
<div style="flex: 1; padding: 10px;">

let sdk = KlarnaSignInSDK(
            returnUrl: URL(string: "app-schema://"),
            eventHandler: self)

To create an instance of the SDK you need to specify the following parameters.

Create and render your own button. The design and implementation are up to you.

​When the user chooses to sign in with Klarna, call the SDK's signIn() function. This will render the authentication flow. When the flow completes, one of the two methods in your event handler will be called.

    @objc func myButtonTapped() {
        self.sdk.signIn(
            clientId: "clientID",
            scope: "scope",
            market: "market",
            locale: "locale",
            presentationContext: self)
    }

The parameters that you'll need to pass to signIn() function are the following:

When the authentication flow is complete, the klarnaComponent(_:dispatchedEvent:) method of your event handler will be called.