Online transactions are conducted in a card-not-present environment where merchants cannot physically inspect the cards and verify their validity, nor can they verify the identity of the cardholders. The online transaction process has evolved to meet these challenges. In order to understand how eCommerce transactions are processed, merchants need to first know these core processing actions:
- Authorization. Authorization is the process by which the card issuer approves (or declines) a card purchase. The authorization takes place at the time the transaction occurs.
- Authentication. Authentication is the process of verification of the cardholder and the card. During the authorization process the merchant should use fraud prevention services to validate the cardholder's identity and the card being used.
- Settlement. Once a product has been shipped or a service provided to the customer, the merchant can initiate the settlement of a transaction through their acquiring bank and trigger the transfer of funds into the merchant account.
There are several participants in an online card transaction:
- Card Issuer. Card issuer is a financial institution that issues payment cards and contracts with its cardholders for repayment of transactions.
- Cardholder. Cardholder is an authorized user of payment cards. In order to make an online purchase, the cardholder must use a web browser to interact with the eCommerce website.
- Acquiring Bank. Acquiring bank (also called an acquirer or a merchant bank) is a financial institution that contracts with merchants to accept and process cards for payment of products and services.
- ECommerce Merchant. ECommerce merchant is an authorized acceptor of payment cards for the payment of products or services it provides.
- Processor. Processor is a financial institution that provides authorization, clearing or settlement services for merchants and merchant banks.
- Merchant Services Provider. A merchant services provider is a third party agent that has a direct relationship with a merchant. The merchant services provider processes or transmits card account numbers on behalf of the merchant. A merchant services provider may also provide services such as shopping carts, payment gateways, website hosting, data storage and clearing and settlement messages.
- Credit Card Association. The Credit Card Associations of Visa and MasterCard support the electronic transmission of all of their card authorizations between acquiring banks and card issuers and facilitate the settlement of funds.

