SaaS is an acronym for Software-as-a-Service, a way of delivering software applications over the internet, rather than installing them on local devices. SaaS applications are hosted and maintained by a service provider, who charges a periodic or per-use fee for the access. SaaS applications can be accessed from any device that has a web browser and an internet connection, making them convenient and flexible for users. SaaS applications can also adjust automatically to the demand, saving costs and resources for the service provider and the users.

SaaS is one of the main types of cloud computing, along with Infrastructure-as-a-Service (IaaS) and Platform-as-a-Service (PaaS). Cloud computing refers to the provision of computing services, such as servers, storage, databases, networking, software, analytics, and intelligence, over the internet. Cloud computing enables users to access services on demand, pay only for what they use, and avoid the hassle of managing and maintaining their own IT infrastructure.

SaaS has many advantages for both service providers and users. For service providers, SaaS simplifies the complexity and cost of developing, distributing, updating, and supporting software applications. For users, SaaS offers easy access to a variety of software applications that can meet their personal or business needs. SaaS also eliminates the need for buying, installing, updating, or maintaining software licenses or hardware. Some common examples of SaaS applications are email, calendaring, office tools, customer relationship management (CRM), enterprise resource planning (ERP), document management, and collaboration tools.