A shopping cart is a piece of software that acts as an online store's catalog and ordering process. Typically, a shopping cart is the interface between a company's Web site and its deeper infrastructure, allowing consumers to select merchandise; review what they have selected; make necessary modifications or additions; and purchase the merchandise.

Shopping carts can be sold as independent pieces of software so companies can integrate them into their own unique online solution, or they can be offered as a feature from a service that will create and host a company's e-commerce site.