Business2Business (B2B) e-Commerce is about the transactions between businesses, rather than business and consumer.

In the past this was achieved using EDI (Electronic Data Interchange) - a direct, point to point link from one company's ERP (Enterprise Resource Planning) system to another. The disadvantage of this was that if a company wanted to trade electronically with many different companies, they would need a link for each. Trading Exchanges act like a mail service, delivering transactions from one member company to another, elimiating the need for point to point connections. They can provide several services such as order management, collaboration tools and e-sourcing/auctions.

One of the most common ways of transmitting transaction documents between businesses and exchanges is using an XML (eXtensible Markup Language) based language. These include xCBL (XML Common Business Language), UBL (Universal Business Language) Microsoft .net and cXML (Commerce eXtensible Markup Language). Enterprise Application Integration (EAI) allows businesses to link up the various applications and systems they have to each other and to e-Commerce applications.