PunchOut is an e-procurement software application from Ariba that makes it possible for a buyer to access a supplier's Web site from within the buyer's own procurement application. The buyer leaves ("punches out" from) their company's system and goes to the supplier's Web-based catalog to locate and order products, while their application transparently maintains connection with the Web site and gathers pertinent information. A vendor catalog that is enhanced for this process is known as a punchout catalog. PunchOut enables communication between the software and the Web site so that relevant information about the transaction is delivered to the appropriate channels. Ariba based their product on commerce XML (cXML), which comprises a meta markup language and a protocol for data exchange between applications. RoundTrip, from Commerce One, and products based on Open Buying over the Internet (OBI) are similar to PunchOut, and are sometimes referred to as punchout solutions.
There are a number of different e-procurement models. The earliest model relied on a point-to-point connection such as Electronic Data Interchange (EDI). In this model, each buyer or seller might have to adapt their transaction mechanisms separately for each trading partner. Two other models, developed to streamline these processes, are becoming increasingly common: the sell-side model, in which the vendor's information is hosted on their own (or a service provider's) server and accessed from within the buyer's procurement system; and the buy-side model, in which the information from multiple vendors is organized into an application that resides on the buyer's server. PunchOut, and similar products based on the sell-side model, allow buyers to access all the information on the vendor's Web site, rather than the selected information that is collected for the buy-side application.