Payment Service Provider (PSP)

The PSP is the interface between your store, the payment networks and the banks. It authorizes payments, handles fraud screening, collects funds and pays them out to you in batches. Well-known providers include Stripe, Adyen, Mollie, PayPal and Klarna, plus Shopify Payments as the integrated option.

Your payment-method mix drives conversion, and it is regional: in the DACH market, for example, customers expect Klarna (invoice, installments and Pay Now), PayPal, Apple Pay and Google Pay alongside credit cards. Missing a market's preferred payment methods is one of the most common causes of checkout abandonment.

Economically, fee structures matter: the per-transaction rate, fixed fees, chargeback costs and — on Shopify — the additional transaction fee charged when you use an external PSP. It is worth calculating whether Shopify Payments or an external provider is cheaper for your volume.