start

Create a session and start Headless Universal Checkout with its clientToken and your custom settings. Once the session is configured on the SDK the completion handler will be called.

SWIFT

func start(
    withClientToken clientToken: String,
    settings: PrimerSettings? = nil,
    delegate: PrimerHeadlessUniversalCheckoutDelegate? = nil,
    uiDelegate: PrimerHeadlessUniversalCheckoutUIDelegate? = nil,
    completion: @escaping (_ paymentMethods: [PrimerHeadlessUniversalCheckout.PaymentMethod]?, _ err: Error?) -> Void
)

​

Parameters

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clientToken · String · required

Client token as returned by the create client session call

settings · PrimerSettings · Optional

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paymentHandling · enum PrimerPaymentHandling

Use this to set you payment handling flow. Defaults to .auto.

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auto · default

Primer SDK will create the payment and handle the flow.

manual

If you use the manual flow, make sure you add the primerDidTokenizePaymentMethod(_:decisionHandler:) delegate function of PrimerDelegate, create a payment on your backend and call the decisionHandler of the delegate function once you receive your backend’s response.

localeData · PrimerLocaleData

Forces some payment methods’ locale.

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languageCode · String · required

Forces the language code (e.g. en). Defaults on your app’s language code if available.

regionCode · String

Forces the language code (e.g. US). Defaults on your app’s region code if available.

paymentMethodOptions · PrimerPaymentMethodOptions

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urlScheme · String

⚠️ Required for some payment methods (e.g. PayPal).

This option sets the deeplink schema used when redirecting back from 3rd party applications to your app.

applePayOptions · PrimerApplePayOptions

⚠️ Required when using Apple Pay in your integration.

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merchantIdentifier · String · required

Set it to the merchant identifier as it is shown in your Apple Pay certificate.

merchantName · String · deprecated

Set it to the merchant name that you want to be shown on the Apple Pay screen. Deprecated, use ClientSession instead.

isCaptureBillingAddressEnabled · Bool

Defaults to false. Set to true to let Apple Pay capture the customer’s billing address.

Use BillingOptions to configure required billing fields.

showApplePayForUnsupportedDevice · Bool

If in some cases you don’t want to present ApplePay option if the device is not supporting it set this to false. The default value is true.

Default value is true. Set to false if you do not want to present Apple Pay option on unsupported devices.

checkProvidedNetworks · Bool

Flag introduced to enable the initiation of the ApplePay flow even when no cards are present in the Wallet. To enable the feature, set this to false. The default value true.

Default value is true. This flag supports the old behavior where Apple Pay flow might not present if there are no cards in the Wallet.

shippingOptions · ShippingOptions

Configure shipping options for Apple Pay.

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shippingContactFields · Array of RequiredContactField

Specify which contact fields are required for shipping.

requireShippingMethod · Bool

Indicate if a shipping method is required.

billingOptions · BillingOptions

Configure billing options for Apple Pay.

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requiredBillingContactFields · Array of RequiredContactField

Specify which contact fields are required for billing.

allowedCardTypes · Array of CardType

Restrict the card types Apple Pay offers. Supported values: .credit, .debit. When omitted or empty, all card types are offered.

klarnaOptions · PrimerKlarnaOptions

⚠️ Required when using Klarna in your integration.

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recurringPaymentDescription · String · required

Set the payment description that will be shown on the Klarna screen.

threeDsOptions · PrimerThreeDsOptions

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threeDsAppRequestorUrl · String

Set the iOS Universal Link that’s used to call your app after an out-of-band (OOB) authentication. Supported in 3D Secure protocol versions 2.2.0 and after.

stripeOptions · PrimerStripeOptions

⚠️ Required when using Stripe ACH in your integration.

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publishableKey · String?

Set the Stripe publishable key.

mandateData · MandateData?

One of:

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fullMandate(text:) · MandateData

The full text that you would like to be displayed to the user before they accept/decline the mandate.

templateMandate(merchantName:) · MandateData

A merchantName that will be used as part of our predefined mandate template.

uiOptions · PrimerUIOptions

Set the uiOptions for custom UI options of the Primer SDK.

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isInitScreenEnabled · Bool

Set to false to hide the loading screen before the Universal Checkout or the Vault Manager. Defaults to true.

isSuccessScreenEnabled · Bool

Set to false to hide the screen after a successful payment, or tokenization on the vault flow. Defaults to true.

isErrorScreenEnabled · Bool

Set to false to hide the error screen when an error occurs. Defaults to true.

dismissalMechanism · enum DismissalMechanism

Set the mechanism for dismissing Universal Checkout. Options are:

• gestures: The dialog can be dismissed by tapping outside or by swiping down.
• closeButton: A close button is provided, allowing users to dismiss the dialog manually.

theme · PrimerTheme

Set a custom theme for Primer SDK.

appearanceMode · enum PrimerAppearanceMode

Control the SDK’s appearance mode independently of the system setting. This allows apps to force light or dark mode regardless of the device’s appearance setting.

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system · default

Follow the system’s appearance setting (default behavior).

light

Force light mode appearance regardless of system setting.

dark

Force dark mode appearance regardless of system setting.

cardFormUIOptions · PrimerCardFormUIOptions?

Configure the card form UI options.

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payButtonAddNewCard · Bool

When set to true, the Drop-In’s card form pay button will show “Add new card”; otherwise it will show “Pay $x.xx”.

debugOptions · PrimerDebugOptions

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is3DSSanityCheckEnabled · Bool · required

clientSessionCachingEnabled · Bool · Default: false

Before enabling the flag to true it’s recommended to reach out to Primer support for additional verification since there are edge cases where it’s not advised.

Indicates whether client session caching is enabled.

When set to true, responses from the server will be cached on the client side, allowing for faster subsequent access to the same data within the cache duration. When set to false, every request to the server will be processed without utilizing any client-side cache, ensuring that the client always receives the most up-to-date data.

apiVersion · PrimerApiVersion · Default: PrimerApiVersion.V2_4

Indicates the API version to use when interacting with the Primer backend. Options are:

• PrimerApiVersion.V2_4 - will use ApiVersion 2.4

Note that this is optional, if a value is not supplied, ApiVersion V2.4 will be used by default.

delegate · PrimerHeadlessUniversalCheckoutDelegate · Optional

Set the delegate to receive updates of the checkout lifecycle.

uiDelegate · PrimerHeadlessUniversalCheckoutUIDelegate · Optional

Set the UI delegate to receive UI updates.

completion · (_ paymentMethods: [PrimerHeadlessUniversalCheckout.PaymentMethod]?, _ err: Error?) -> Void · Optional

The completion handler will be called once the session has been configured on the SDK, and it will provide you with available payment methods for the session