Software as a service (SaaS, typically pronounced [sæs]), sometimes referred to as «on-demand software,» is a software delivery model in which software and its associated data are hosted centrally (typically in the (Internet) cloud) and are typically accessed by users using a thin client, normally using a web browser over the Internet.
SaaS has become a common delivery model for most business applications, including accounting, collaboration, customer relationship management (CRM), enterprise resource planning (ERP), invoicing, human resource management (HRM), content management (CM) and service desk management. SaaS has been incorporated into the strategy of all leading enterprise software companies.
According to a Gartner Group estimate, SaaS sales in 2010 have reached $10B, and are projected to increase to $12.1b in 2011, up 20.7% from 2010. Gartner Group estimates that SaaS revenue will be more than double its 2010 numbers by 2015 and reach a projected $21.3b. Customer relationship management (CRM) continues to be the largest market for SaaS. SaaS revenue within the CRM market is forecast to reach $3.8b in 2011, up from $3.2b in 2010.
The term software as a service (SaaS) is considered to be part of the nomenclature of cloud computing, along with infrastructure as a service (IaaS) and platform as a service (PaaS).