Industry Terms: Payment Gateway

Posted: August 10, 2012 | Updated: August 10, 2012

This is the latest installment in The Official Merchant Services Blog’s Knowledge Base effort. We want to make the payment processing industry’s terms and buzzwords clear. We will eliminate any and all confusion merchants might have about how the industry works. At Host Merchant Services, we promise to deliver personal service and clarity. So we’re going to take some time to explain how everything works. This ongoing series is where we define industry related terms and slowly build up a knowledge base and as we get more and more of these completed, we’ll collect them in the resource archive for quick and easy access.

Payment Gateway

Today we will focus on Payment Gateways and how they work, in order to wrap up our week of E-commerce driven content. A payment gateway allows E-commerce merchants to accept credit cards on their websites. Sensitive payment information is encrypted by the gateway to ensure that it passes securely between the customer and the merchant. We have defined a POS, or point of sale system already for the Knowledge Base. A payment gateway can be considered a virtual point of sale system. The gateway acts as a “middle man,” allowing communication between online shopping carts or virtual terminals and the banks processing the transaction.

The process can be broken down like this, it starts when a customer places an order on a website by pressing the “Submit Order” button in an online shopping cart. The payment gateway then forwards the transaction information to the payment processor used by the merchant’s acquiring bank. From there the payment processor forwards that information to the appropriate card association (ex Visa, MasterCard). The credit card issuing bank receives the request, or the Authorization and does the necessary credit or debit check and then sends a response back to the processor in the form of an approval code (ex approved, denied). Next the processor forwards the authorization response back to the payment gateway. After receiving the response, the gateway forwards it on to the website, which then evaluates it as a relevant response and relays the outcome to the merchant and cardholder. Finally, the merchant then fulfills the customers order, then after a batch the acquiring bank receives the funds, and deposits them into the merchants bank account.

Payment gateways can be stand-alone systems designed for integration with other 3rd party systems, or they can be bundled with their own shopping carts and virtual terminals. It’s worth noting that most merchants will not need to install additional software on their own servers to run a basic payment gateway. Some payment gateway providers are simple to implement, but do not offer much customization. Others are more complex but can be customized to your needs.

Host Merchant Services offers a variety of E-commerce solutions to fit your business, including Transaction Central, our own cutting edge in house payment gateway. HMS is able to interface with most of the major Payment Gateways out there, including We also offer unparalleled protection for all of our merchants in the form of our PCI Compliance Initiative.


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