Websystem has worked a lot with different types of payment solutions and web shops. Everything from sending bank files for payment to build payment solutions towards Payson and Klarna.
When it comes to integration with Klarna, we maintain the Drupal module. We thus know how to integrate payment solution towards Klarna.
We encoded a system where athletic clubs can pay all their fees via bank files.
We have developed webshops who manage their payments through PayPal or towards Payson.