Integration between e-commerce and Klarna Checkout (PHP). Only one file needed.
This build has been developed for Tuspe's webshop. All the information is saved in SQL, but normally I just get product information from there and other things from the session ($cart_data). You need to replace shop_merchant_id, shop_merchant_secret, SQL query and content of $cart_data for your own information.
Suggestions for improvement are welcome.