On an eCommerce site, a shopping cart is a piece of software that enables purchasing a product or service. An online shopping cart is software that allows users to choose products and purchase them via the internet.
In a physical store, a customer could browse, select a product from the shelf, then proceed to the checkout counter to complete the transaction. Alternatively, they could push a cart around the store collecting multiple items before checking out.
Customers need a way to replicate this experience on an e-commerce platform. They can choose things and store them in a virtual cart using an online shopping cart on their computer or mobile device. Once they are ready to checkout they can pay online.
