Authorise payments with the iOS SDK

If you have an integration that can create a payment and get the associated id, you can use the iOS SDK to authorise it.

Before you start

Register a redirect URL in Console. Go to Console > Settings > Allowed redirect URIs to do this. Your user is redirected back to your redirect URL, typically your website or application, at the end of the payment journey.

You also need an integration that can create a payment, and get a payment id, to start the iOS SDK. Learn more about how to create a payment, and authenticate, and sign your requests (our payment quickstart guide provides an overview).

Configuration overview for payments with the iOS SDK

There are five general steps to configuring the iOS SDK with the Payments API v3:

1. Install the SDK
2. Start the SDK
3. Process the payment authorisation
4. Handle the authorisation result
5. Display the payment result screen

1. Install the SDK

There are two different methods you can use to install the iOS SDK. The Swift Package Manager or Cocoapods.

Install the SDK with Swift Package Manager

The SDK is released as a compiled binary in the form of a series of XCFrameworks artefacts.

To install the SDK using Swift Package Manager:

1. Open your app in Xcode.
2. In the Project Navigator, go to the project.
3. In the Project panel, select the project.
4. Go to the Package Dependencies tab.
5. Select +.
6. Enter https://github.com/Truelayer/truelayer-ios-sdk in the search bar and select Enter.
7. Select Add Package.
8. Follow the steps in Xcode to install the SDK.

Install the SDK with CocoaPods

To install the SDK through CocoaPods, specify TrueLayerPaymentsSDK in your Podfile:

pod 'TrueLayerPaymentsSDK

2. Start the SDK

The SDK has two methods: configure(environment:visualSettings:) and processPayment(context:then:), which are used to invoke the SDK and process payments respectively.

The interface that exposes all functions can be accessed through its singleton TrueLayer.Payments.manager.

To use the SDK, you have to invoke its configure(environment:visualSettings:) method. This method should be invoked once.

You also need to specify the environment to process payments in: .production or .sandbox. The environment determines which TrueLayer backend your app will use to process the payment.

You should initialize the SDK inside your AppDelegate, SceneDelegate, or any other container to manage your dependencies.

The following example shows how this can be done using the SceneDelegate:

import TrueLayerPaymentsSDK

class SceneDelegate: UIResponder, UIWindowSceneDelegate {
  func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    guard let windowScene = scene as? UIWindowScene else { return }
    
    Task {
      await TrueLayer.Payments.manager.configure(environment: .sandbox)
    }
  }
}

3. Process the payment authorisation

Once your app has obtained the payment identifier (payment id) and the token (access_token)from the backend, it can use the SDK to process the payment. This is an example of how to process a payment in Swift:

TrueLayer.Payments.manager.processSinglePayment(
  context: TrueLayer.Payments.Models.SinglePayment.Context(
    identifier: // Your payment ID,
    token: // Your resource token,
    redirectURL: // Your redirect URL
    preferences: // Your possible preferences like type of presentation and country code.
  )) { processResult in
    switch processResult.result {
      case .success(let success):
        // Handle `TrueLayer.Payments.Models.SinglePayment.State`.
        print(success.state)

      case .failure(let failure):
        // Handle `TrueLayer.Payments.Models.SinglePayment.Error`.
        print(failure.error)
    }
    
    // Handle `resultShown`.
    print(processResult.resultShown)
}

Payment parameters

These are the parameters used above when you process the payment:

• identifier: The payment id retrieved from your backend.
• token: The payment access_token retrieved from your backend.
• redirectURL: The destination where the user should be redirected once the authorisation flow is done outside of the app (bank website, HPP). This is usually your app's redirect URI. set in Console.
• preferences The preferences parameter enables you to customise the authorisation flow. It contains the following options:
  • presentationStyle: Determines how the SDK should be presented.
  • preferredCountryCode: The preferred country to use when displaying the providers. If the country is invalid, or does not include any providers, the value will fallback to the user's locale.
    shouldShowResultScreen: Whether the TrueLayer SDK should show the payment result screen. See the display the payment result screen section below.
  • maximumResultScreenTimeout: The maximum timeout for refreshing the payment result screen. See the display the payment result screen section below.

When the user is redirected back to your app from their bank app or website, we recommend that you re-invoke processSinglePayment(...) with the same Context. This is because some banks require further input from the user, which the SDK can present.

4. Handle redirects and display the authorisation result

Once the redirects are complete, you receive a success or error callback, which renders in the payment result screen.

Handle redirects from the provider

At the end of a redirect flow the bank app will relaunch your app with the return URI you specified in Console.

In your application fetch the redirect parameters. These must include the payment id (or identifier in the SDK). For more information on handling deep links, follow the iOS documentation here and here.

Whenever you are redirected to your app, you should reinvoke the SDK, until you receive a success or error callback.

By default the SDK offers a payment result screen, which displays the result of the payment and advises the user on what to do in case of a failed payment. If you disable the payment result screen, a noneShown result is returned, you can use the success or error callback to render a screen for your user when they return to your app.

We also recommend that you check the payment status to confirm the result of a payment.

Payment success results

The SDK returns the following results for TrueLayer.Payments.Models.SinglePayment.State if a payment is successful or in progress:

Payment failure results

The SDK returns the following results for TrueLayer.Payments.Models.SinglePayment.Error if payment authorisation has failed for any reason.

Check the status of a payment

You can use the following method in the iOS SDK to get the current status of a payment:

func paymentStatus(
  paymentIdentifier:,
  resourceToken:
) async throws -> TrueLayer.Payments.Models.SinglePayment.Status

These are the different payment statuses the SDK can return for TrueLayer.Payments.Models.SinglePayment.Status:

5. Display the payment result screen

We recommend that you display the payment result screen to your customers (learn more about the payment result screen). The payment results screen shows your user the result of the payment. If it fails, it recommends the appropriate action for them to take to resolve the problem.

Payment result screen configuration

Configuration options for the payment result screen are within the Preferences object when you begin to process the payment.

To enable the payment result screen in the iOS SDK, ensure that the shouldShowResultScreen within the Preferences object retains its default value of true. This ensures that the iOS SDK displays the result of a payment at the end of the authorization flow.

This screen automatically refreshes until the payment is creditable, or until a maximum timeout is reached. You can reduce the duration until the timeout by providing a value for maximumResultScreenTimeout within Preferences. By default, this timeout is 10 seconds, and cannot be set longer as the SDK uses 10s if you pass a greater value.