• Your customer: (person donating or buying) Typically, a holder of a payment instrument-such as a credit card, debit card, or electronic check-from an issuer.
• The issuer: (customer's credit card company) A financial institution, such as a bank, that provides your customer with a payment instrument. The issuer is responsible for the cardholder's debt payment.
• The merchant: (you) Your e-commerce site, which sells goods or services to the cardholder via a Web site. A merchant that accepts payment cards must have an Internet Merchant Account with an acquirer.
• The acquirer: (i.e. First of Omaha) A financial institution that establishes an account with you, the merchant, and processes payment authorizations and payments. The acquirer provides authorization to the merchant that a given account is active and that the proposed purchase does not exceed the customer's credit limit. The acquirer also provides electronic transfer of payments to your account, and is then reimbursed by the issuer via the transfer of electronic funds over a payment network.
• The payment gateway: (i.e. Verisign Payflow Link) Operated by a third-party provider, the gateway system processes merchant payments by providing an interface between your e-commerce site and the acquirer's financial processing system.
• The processor: (i.e. First of Omaha/Vital) a large data center that processes credit card transactions and settles funds to merchants, the processor is connected to your site on behalf of an acquirer via a payment gateway.

The basic steps of an online payment transaction using a payment gateway system include the following:

1. The customer places an order online by selecting items from your Web site and sending you a list. Your site often replies with an order summary of the items, their price, a total, and an order number.
    
2. The customer sends the order, including payment data, to you. The payment information is usually encrypted by an SSL pipeline set up between the customer's Web browser and your Web server's SSL certificate (i.e. Equifax).
    
3. Your e-commerce site requests payment authorization from the payment gateway, which routes the request to banks and payment processors. Authorization is a request to charge a cardholder, and must be settled for the cardholder's account to be charged. This ensures that the payment is approved by the issuer, and guarantees that you will be paid.
    
4. You confirm the order and supply the goods or services to the customer.
    
5. You then request payment, sending the request to the payment gateway, which handles the payment processing with the processor.
    
6. Transactions are settled, or routed by the acquiring bank to your acquiring bank for deposit.

Everything from electronic check processing to make user friendly electronic payments for online payment processing make sure your SSL certificate is up to date and you're all set.