Authorize.net is a payment gateway service provider that allows merchants to accept credit card and electronic check payments over websites and the internet. It works by having the customer submit their credit card details, then the merchant submits the transaction details to Authorize.net through a secure connection. The transaction is then passed through the customer's bank, credit card network, and merchant's bank before funds are credited to the merchant's account within two days. Addon Solutions offers services integrating websites with the Authorize.net payment gateway using technologies like PHP, ASP.NET, and Java.