AhsanAllahu ilaykum, Is it riba if I have to pay for something and the app (Klarna) gives me the option to pay later, but the price is €2 higher than the original? It’s not based on percentages or anything like that. Barakallahu feekum

From what I understand from your question, this is not authorized by the merchant. I do not know what this specific application is, and I do not care for the specific application; what I care about is the form of the transaction. As I understand it, they will pay on your behalf as if they have loaned you the money, and then you have to pay them back an extra amount. If this is the case, then this is forbidden and it is riba. However, if the merchant is giving you the option to sell you the merchandise later for a higher price, or over installments, then this is allowed.