What is a Payment Gateway?

A payment gateway is an online service provider that connects an electronic shopping cart or virtual terminal/POS to an electronic payment processor. It is your gateway to the rest of the payments infrastructure that allows you to accept electronic forms of payment.

The main function of a gateway is to pass authorization, payments, and settlement data securely to and from the merchant’s website to the merchant’s processor. The merchant processor in turn connects to the card association (or “network”), which connects to the card issuing bank.

The Payments Value Chain
The payments ecosystem is very fragmented, due to a high degree of specialization, and any given payment transaction typically passes through at least five or six different parties, which we will call the payments value chain. When a customer swipes their credit card to make a payment for a purchase, it usually takes just a couple of seconds for the point of sale system to prompt for a signature or a PIN, and another few seconds to complete the transaction and print out a receipt. It is testament to the robustness of the electronic payments system that the end user is typically completely unaware of the complexity of the underlying plumbing that makes electronic payments possible.

A typical payments value chain may comprise of:

  • Payment gateways
  • Merchant account providers (or merchant acquirers)
  • Processors
  • Networks (card networks)
  • Issuers

The following sections will explain, in brief, the role of each of these parties and some of their key functions.

Payment gateways
The term payment gateway is often used loosely to describe a variety of payment service providers, or PSP’s, that a merchant deals with in order to accept electronic payment methods. However, in the strictest sense, a gateway is an intermediary that sits between a merchant’s virtual POS (point of sale) or online shopping cart, and serves as the first interface from the merchant to the rest of the payments value chain.

The gateway essentially ferries messages between the merchant and the payments system, and these messages can be card authorizations, capture (or settlement) transactions, voids, or refunds. In all these cases, messages travel to and from the merchant and the card issuing institution (typically a bank or credit union).

There are two type of gateways:

  • Independent Gateway Providers: These are gateways that can connect to 3rd party merchant account providers or processors.
    Examples are: Authorize.net, SagePay, Paypal Payflow, Stripe (some of the most popular gateways). The advantage of going with an independent gateway provider is that you are not bound to a particular merchant account provider, and could easily switch if offered a better price or superior services.
  • Full Service Payment Providers: These are owned by merchant acquirers or processors, and connect only to the processors that are affiliated with that merchant account provider. Often times the advantage of using a full service payment provider (those that provide a gateway, processing services, and/or merchant acquiring services) is that you get better processing fees and cheaper (often free) gateway services. The other advantage is that they’re a one-stop shop, offering a single customer contact for both the gateway, processor, and acquiring bank (for example, Chase Paymentech). Since the gateway and processor come pre-integrated, the time and effort to connect the gateway and processor is negligible.
    Examples of Full Service Payment Providers with a gateway or processor that can be integrated into Kaptio  are: Orbital by Chase Paymentech, Merchant eSolutions, Litle & Co., Ingenico ePayments, Quick Gateway by Qvalent, Website Payments Pro by PayPal.

It is important to consider the pros and cons of each type of gateway before selecting one.

Merchant account providers
Merchant account providers (or merchant acquirers) provide merchant bank accounts that are capable of receiving and transmitting electronic payment funds. The merchant account provider owns the merchant relationship, and is most often the primary interface to the merchant for everything related to payment acceptance, processing and customer service. Their typical responsibilities are:

  • Signing up merchants
  • Merchant marketing and POS sales
  • Disputes and chargeback processing
  • Setting price / MDR (merchant discount rate)
  • Underwriting merchant risk
  • Connecting to the merchant processor

Merchant processors
Merchant processors receive and store merchant transaction data and process payment transactions by connecting to the “backbone” networks like Visa and Mastercard. In effect they are the switch that receives the card details from the gateway and decides which network to route them to. The receive data back from the networks and pass them back along to the gateway. Some payment processors also provide other payment services, such as payment gateway and acquiring services.

Networks provide the payment infrastructure (“pipes”) to route card payment transactions between merchant processors and issuers. Key functions are:

  • Acceptance network brand marketing and awareness
  • Transmission of payment data to issuers
  • Risk management

Of these functions, the first is probably the most critical, as it drives merchant card acceptance and consumer demand for specific network-branded cards. Most consumers only know that they have a Visa or a MasterCard card, not the issuing bank. This is not a coincidence, but a carefully crafted branding strategy on the part of the card associations/networks, and they have done this by funding and driving the creation of issuer-agnostic, consumer-friendly card features and programs, like zero-liability or travel/accident/rental car insurance etc, merchant-specific loyalty program promotions.


Issuers are the banks that issue payment cards. They serve two broad functions:

  • Consumer-side demand generation. This includes:
    • Consumer marketing & acquisition
    • Credit risk analysis
  • Provision of credit / lendingPayment processing
    • Authentication and authorization approval
    • Receipt, processing, and storage of issuer transaction
    • Credit/debit card servicing (billing, statementing, payment collection)