A payment gateway is a tool that safely transmits online transaction data to the processor to continue the transaction life cycle. A payment processor takes part in the transaction, transferring data between you, the client, the issuing bank (the bank that issued your client’s card), and the acquiring bank (the bank in which your company account is registered). Simply put, the difference is that the payment gateway is an instrument that reports on the execution or rejection of transactions, and the processor facilitates the transaction itself.