The purpose of this study is to investigate customers’ needs in an online checkout system andexplain why the payment provider Klarna is so sought-after. This is of particular interest tocompanies working with e-commerce. Using cognitive walkthrough plus a test survey, this study analyses test participants experience on a test-store. Using an independent second survey, customers preferences ofpayment method, their motivation on why those payment method(s) are preferred, their preference of delivery method and the methods they mostly use today when shopping online are investigated. Using a heuristics evaluation, an analysis of the features that make Klarna apopular payment provider and those that Klarna offers but are not offered by Obseum is examined. The results show that all test-participants find the test-store easy to navigate through and give it, in total almost top score on their experience. The results of the survey show that the most preferred payment provider is Swish due it being a quick and smooth payment provider andalso because most respondents are from Sweden. The results of the evaluation show that Klarna offers the customer to save their personal information for later use when using Klarna,which Obseum does not currently offer. In conclusion, this study shows that customers like choice in payment systems offered by an online store and having the option of payment later, as provided by Klarna, is very popular with customers. Further studies are needed to investigate customers’ needs from outside of Sweden and to what the costumers usually buy online.