To ensure a robust, seamless, and customer-friendly Klarna integration through Worldline, it is essential to follow a set of best practices. This checklist will help you finalize your Klarna setup using Worldline APIs and prepare for go-live with full functionality and compliance.

Upload your logo and brand name - ensure the assets meet Klarna’s format and resolution requirements.

• Benefit: Klarna will reflect your brand across touchpoints with the consumer, improving recognition and trust.

Add all available order details to the line items in your API requests to Worldline.

• Benefit: Enables enhanced fraud detection, enriched post purchase experience with detailed receipts.

Ensure consistency across your systems and communications with customer by sharing your customer-facing order ID ( order.references.merchantReference ).

• Benefit: The information is displayed across all touch points between the customer and Klarna, including Klarna app and emails. It is also a key data point to support your reconciliation process and dispute management.

This data could be shared via redirectPaymentMethodSpecificInput.paymentProduct838SpecificInput.interoperabilityData , which is a serialized JSON object that follows Klarna’s Interoperability Data Schema or via structured objects in Worldline's API.

Include in relevant API calls to provide session and customer context.

• Benefit: Enhances session continuity, allowing for greater personalization and improved conversion rates. Additionally, redirectPaymentMethodSpecificInput.paymentProduct838SpecificInput.interoperabilityData will support processing for specific MCCs.

In an Advanced integration, you will receive an interoperability_token from Klarna when the customer interacts with services powered by WebSDK, such as Klarna On-site Messaging, Sign in with Klarna, or Express Checkout.

If interoperability_token is available, include it in your API requests to Worldline.

• Benefit: Links customer context across touch points for a smoother experience.