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

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:

Open your app in Xcode.
In the Project Navigator, go to the project.
In the Project panel, select the project.
Go to the Package Dependencies tab.
Select +.
Enter https://github.com/Truelayer/truelayer-ios-sdk in the search bar and select Enter.
Select Add Package.
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 and authorise the payment

Once your app has obtained the payment identifier (payment id) and the token (resource_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 resource_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.

📘
To ensure that any redirects back to your app work properly, use universal links for the redirect URI and other links throughout your app. Read the Apple documentation for more information on setting up and troubleshooting universal links.
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.

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

The flow for the authorisation through the iOS SDK where the user is sent to their bank to authorise the payment, then redirected to the Client App.

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.

📘
When your user's default browser is not Safari, some banks and TPP applications may fail to redirect the user.
To fix this, go to your iOS app code. Navigate to your info.plist and add the entry LSApplicationQueriesSchemes. Set its Type to string and Value to https.
The Information Property List with LSApplicationQueriesSchemes added.
For more information, see Apple's documentation on Launch Service Keys.

Payment success results

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

`TrueLayer.Payments.Models.SinglePayment.State` value	Description
`.executed`	The payment has been sent to the bank to complete.
`.authorized`	The user authorised the payment with the bank.
`.redirect`	The user has been redirected to the bank to authorise the payment.
`.settled`	The funds have reached the beneficiary account.
`.wait`	The SDK flow is complete, but a decoupled authorisation action is still pending with the user and/or the bank.

Payment failure results

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

Expand to see all payment failure results

`TrueLayer.Payments.Models.SinglePayment.Error` value	Description
`.authorizationFailed`	The user could not authorise the payment with their bank.
`.connectionIssues`	There was an issue while connecting to the internet.
`.generic`	A unexpected error, the error will be passed as a `String` parameter.
`.invalidToken`	The token used to make the payment doesn't have the necessary `scopes`).
`.invalidRedirectURI`	The redirect URI passed to the SDK is invalid.
`.paymentExpired`	The user took too long to authorise the payment so it expired.
`.paymentNotFound`	The requested payment was not found.
`.paymentRejected`	The payment was rejected by the bank.
`.providerOffline`	The pre-selected provider was offline.
`.sdkNotConfigured`	The SDK configure method has not been called before using it.
`.serverError`	The server encountered an error while processing the answer.
`.blocked`	The payment has been blocked due to a regulatory requirement. This may happen if the PSU fails a sanctions check.
`.invalidAccountDetails`	The payment failed because either the creditor's or debtor's account details were invalid.
`.invalidAccountHolderName`	The payment failed because the account holder's name details were invalid.
`.invalidCredentials`	The banking credentials provided by the PSU to log into their bank were incorrect.
`.invalidRemitterAccount`	The account details of the remitter bank account provided during the payment flow were incorrect.
`.invalidRequest`	The payment failed due to invalid data in the request.
`.invalidSortCode`	The payment failed due to an invalid sort code being provided.
`.insufficientFunds`	The PSU did not have the required balance in their account to complete this payment.
`.notAuthorized`	The PSU cancelled the payment or wasn't able to successfully authenticate on the provider's UI.
`.paymentLimitExceeded`	The PSU's payment limit amount with their bank was breached.
`.providerError`	The provider has unexpectedly failed when creating the payment.
`.providerExpired`	The payment failed because the token or exchange code used to communicate with the bank expired.
`.providerRejected`	The provider rejected the payment.
`.unknownError`	The payment failed for an unknown reason on the server side.
`.userCanceledAtProvider`	The payment failed because the user cancelled the authorisation during the payment flow.
`.unexpectedBehavior`	The SDK encountered an unexpected behaviour.
`.userCanceled`	The user canceled the payment.

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:

Status returned in `TrueLayer.Payments.Models.SinglePayment.Status`	Description
`.authorizationRequired`	The payment requires authorisation by the user making the payment.
`.authorizing`	The user is currently authorising the payment.
`.authorized`	The user has authorised the payment with their bank.
`.executed`	The payment has been executed and sent to the bank for completion.
`.settled`	The funds have reached the beneficiary account.
`.failed`	The payment failed. This can be due to various reasons, explained in the `Error` object.

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 whether the payment succeeds or fails. 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.