Sales force.com's platform as a service (PaaS) product is known as Force.com. The Force.com platform allows external developers to create add-on applications that integrate into the main salesforce.com application and are hosted on salesforce.com's infrastructure.

These applications are built using Apex (a proprietary Java-like programming language for Force.com) and Visualforce (an XML-like syntax for building user interfaces in HTML or Flex).