Klarna Integration with Shopware 6 – Full Documentation & Guide

1. Introduction

In a competitive e-commerce ecosystem, offering multiple, flexible payment methods is essential to building trust and reducing cart abandonment. Klarna has established itself as a leader in modern payments, offering options like “Pay Later,” “Pay Now,” and “Pay Over Time” — all optimized for user experience and conversion.

This guide provides a detailed step-by-step walkthrough for integrating Klarna with Shopware 6, an increasingly popular e-commerce platform across Europe and beyond. Whether you’re a Shopware developer, a technical merchant, or a system integrator, this guide will help you implement Klarna with confidence.

We’ll cover:

• Klarna’s value for merchants
• Prerequisites and setup
• Klarna plugin installation (via Admin or Composer)
• Sales channel configuration
• Checkout customization
• Testing Klarna in Sandbox mode
• Going live with Klarna
• Advanced theme and troubleshooting tips

According to Klarna’s internal research, e-commerce stores can see up to 44 % higher conversion rates and 36 % larger average order values when using Klarna Pay Later solutions.

2. Why Klarna?

Klarna’s mission is to simplify purchasing for consumers while reducing risk for merchants. It covers the entire customer payment journey with a variety of modular solutions.

Key Klarna Features:

• Pay Later: Let customers try before they buy. Pay after 14 or 30 days.
• Pay Now: Standard one-time payments via credit/debit cards or bank transfer.
• Financing (Slice It): Customers can split payments into manageable monthly installments.
• Klarna One-click Checkout: Returning Klarna users can complete purchases with a single tap.
• Risk Management: Klarna handles credit and fraud checks, paying you upfront and taking over the risk.
• Developer-Friendly APIs: Klarna offers detailed documentation, SDKs, and test environments.

These offerings are ideal for increasing trust in your checkout and giving your customers more control over how they pay.

3. Prerequisites

Before you begin integrating Klarna, ensure that you meet the following technical and account-based requirements:

Shopware 6 Environment

• Shopware version 6.4+ (official Klarna support)
• Composer installed
• PHP 8.1 or later
• MySQL 8 or MariaDB 10.4+
• DDEV or Docker (optional, for local setup)

Klarna Merchant Account

• Register for a merchant account: https://www.klarna.com/merchant-signup/
• Once approved, you’ll get:
  • API username
  • API password
  • Test credentials
  • Access to Klarna’s Merchant Portal

Klarna distinguishes between Test (Sandbox) and Live environments. Each has different API credentials.

4. Install the Klarna Plugin

There are two ways to install the Klarna Payments plugin for Shopware 6 — via the Shopware Admin (for non-developers) or via Composer (recommended for dev teams and CI/CD).

Option A: Admin Interface (Shopware Store)

1. Go to your Shopware 6 admin panel.
2. Navigate to Extensions → Store.
3. Search for “Klarna Payments”.
4. Click Install → then Activate.

Option B: Install via Composer (Developer Recommended)

composer require klarna/shopware6
bin/console plugin:refresh
bin/console plugin:install --activate KlarnaPayments
bin/console cache:clear

5. Configure Klarna Plugin in Shopware Admin

Once installed, you need to configure Klarna with your credentials and assign Klarna payment methods to your storefront.

Add Klarna API Credentials

1. Go to Settings → Extensions → Klarna Payments.
2. Choose your environment:
   • Test (for development)
   • Live (for production)
3. Enter your API username and API password provided by Klarna.

Optional Plugin Settings

• Logging level (for debugging)
• Auto-capture vs manual capture
• Enable/disable individual payment types (Pay Later, Pay Now, Slice It)

6. Klarna Payment Methods in Shopware

Once activated, Klarna will add several new payment methods:

• Klarna Pay Later
• Klarna Pay Now
• Klarna Slice It (Financing)

Enable Klarna Payment Methods

1. Go to Settings → Payment Methods.
2. Click into each Klarna method and ensure it is:
   • Enabled
   • Assigned to the appropriate sales channels
3. Customize display names and position if needed.

7. Assign Klarna to Sales Channels

To show Klarna options in your storefront checkout:

1. Go to Sales Channels → Storefront → Payment Methods.
2. Check all Klarna payment methods you want to support.
3. Set Klarna Pay Later (or others) as default if desired.
4. Save.

8. Klarna in the Checkout Flow

Klarna will now be available as a payment option at checkout. Depending on the customer’s location, Klarna dynamically shows applicable payment options.

Klarna Checkout Widgets

If using a custom Shopware theme, ensure that Klarna’s JS is not blocked. Klarna uses widgets that integrate with the checkout to show terms, installment breakdowns, etc.

<div id="klarna_container"></div>
<script src="https://x.klarnacdn.net/kp/lib/v1/api.js" async></script>

9. Test Klarna Integration

Before going live, test your setup thoroughly using Klarna’s Sandbox credentials.

Enable Sandbox Mode

1. In plugin settings select Test Mode.
2. Use Klarna-provided Sandbox API credentials.

Test Payment Scenarios

• Approved and rejected payments
• Pay Now, Pay Later, and Slice It flows
• Cancellations, refunds, chargebacks

Klarna test transactions will not appear in your real Merchant Portal. Use playground.klarna.com to review test behavior.

10. Go Live with Klarna

1. Switch Klarna plugin to Live Mode.
2. Replace test credentials with live API keys.
3. Save changes.
4. Test with a real payment in production (low value).
5. Run bin/console cache:clear .

Caution: Klarna orders cannot be transferred from Sandbox to Live. Treat test/live stores as isolated systems.

11. Order Management & Klarna Features

The Klarna plugin enhances the Order View in Shopware admin. Here you can:

• View Klarna-specific transaction data
• Initiate cancellations
• Perform full or partial refunds
• Sync order status updates

Go to: Orders → Select Order → Klarna Tab

12. Advanced Customizations

If you’re working with custom storefronts or themes, consider the following:

Theming Klarna Elements

• Klarna checkout snippets can be themed, translated, or repositioned. If customizing templates:
  • Don’t remove Klarna’s JS include.
  • Keep Klarna containers visible.
  • Test all devices and breakpoints.

Klarna JS Conflicts

Conflicts may occur with other checkout scripts (e.g., Google Pay, PayPal). Use Chrome Developer Tools to inspect and debug.

Add Klarna to Off-Canvas Cart

Klarna supports rendering financing info in mini-carts or product pages. Ask Klarna support for marketing widgets.

13. Troubleshooting & Debugging

Problem	Solution
Klarna not shown at checkout	Make sure payment method is active, assigned to sales channel, and available for the currency.
“Invalid credentials” error	Double-check Sandbox vs Live credentials.
Klarna JS not loading	Ensure scripts are not blocked by Content Security Policy or theme.
Refund fails	Refund might not be allowed yet (e.g., order not captured).
Error: HTTP 403	Check Klarna region settings and IP restrictions.

14. Klarna Compliance & UX Tips

• Branding: Always display Klarna logo where required.
• Checkout Experience: Do not hide Klarna options deeper in the checkout process.
• Financing Disclosure: Show APR rates and legal info when offering installment plans.

15. Conclusion

Integrating Klarna into your Shopware 6 store opens up a world of flexible payment options, optimized checkout experiences, and trust-building features. Whether you’re targeting a mobile-first European market or expanding globally, Klarna is a must-have for modern e-commerce platforms.

This guide walked you through the complete Klarna integration process — from plugin installation to live deployment and advanced customization. With Klarna, you’re not just adding a payment provider — you’re building a smarter and more customer-friendly checkout.