SaaS (Software as a Service)

Software as a Service is a cloud service model in which a consumer uses a provider’s applications running on cloud infrastructure. The provider manages the underlying infrastructure; the consumer may control limited application settings. Access can use a browser, a dedicated client, or a program interface.

Subscription pricing is common but is not the defining technical property. A hosted application can require local configuration, integration, identity setup, and user training. Provider operation does not remove the customer’s responsibilities for permitted data use, access decisions, and checking service results.

For a use-case brief, distinguish the delivery arrangement from the desired outcome. Paying for a hosted invoice application does not demonstrate reduced handling effort. State supported work, dependencies, data export needs, service limits, and the costs of running the complete workflow. Financial ratios such as retention and margin need separate definitions and should not be inferred from the SaaS label.

Related reference: NIST cloud service definitions. Examples and calculations here are illustrative.