Advanced Integration Method (AIM) is the preferred Authorize.Net integration solution, and uses secure sockets layer (SSL) digital certificate technology to connect securely and directly to the Payment Gateway—achieving the highest security for the Internet connection between a merchant and the gateway. Simple Integration Method (SIM) optimizes the security, encryption, and authentication of transactions for merchants that do not have an SSL digital certificate.

AIM and SIM provide the highest levels of secure transaction infrastructure available to merchants building an e-commerce business and directly connecting that their website to the Authorize.Net Payment Gateway.

When using AIM and SIM to connect to the Payment Gateway, a customer enters purchase information (e.g., name, credit card number, etc.) into a payment form on the merchant's website. This payment form is hosted either by the merchant, or the merchant may choose to use Authorize.Net's securely hosted, customizable payment form.

When the customer clicks to submit his or her purchase information, payment information is encrypted using 128-bit SSL technology and sent to an Authorize.Net transaction server. The server sends the data through the authorization network to the appropriate card issuer's bank, using a secure, proprietary connection. When the authorization process is complete—this takes around five seconds—the customer receives an approval or decline response, and the Authorize.Net server stores the transaction. Approved transactions are automatically settled each day and are typically funded within two to three business days.

Merchants can check the status of current transactions submitted directly from their website or run reports on past transaction activity by going to the Authorize.Net Corporate site and logging into their own password-protected Merchant Interface. Online businesses also can use the Authorize.Net Virtual Terminal feature of their Merchant Interface account to enter payment information manually if customers prefer to call in their credit card information.