Software as a service (SaaS) is software provided through a subscription or pay-per-use model and accessed over the internet, allowing multiple customers to use a single platform simultaneously. SaaS has driven significant market growth due to advantages for both vendors and customers, including predictable revenue, lower upfront costs, faster deployment, and easier maintenance for customers, as well as shorter sales cycles and instant updates for vendors. Common SaaS applications include enterprise resource planning, customer relationship management, human resource management, collaboration software, and consumer-oriented services.