A payment service provider is the link between a merchant and the acquirer. The PSP provides the technical means for accepting payments via the merchant’s website or app, as well as other services like risk management, fraud protection and a secure PCI-compliant vault for storing card details. The acquirer is a step further down the chain, receiving payment information from the PSP. The acquirer is a member of a card scheme (e.g. Visa, Mastercard etc.), and acts as the middleman between PSP and card issuer. The acquirer accepts payments on the merchant’s behalf, and forwards any payment requests to the card issuer for approval. Once the transaction has been approved or declined by the issuer, the acquirer notifies the PSP of this status.