What is SaaS?
Also known as: Software as a Service
SaaS (Software as a Service) delivers centrally hosted, multi-tenant software to end users over the internet, typically through a web browser or API, with no local installation or server management required.
SaaS, short for Software as a Service, is a cloud computing delivery model where a provider hosts and maintains the entire software stack in their own data centers and makes the application available to customers over the internet, usually on a subscription basis. Customers access the software through a web browser, thin client, or programmatic API, and pay for usage by seat, consumption, or a flat monthly fee.
The provider handles all underlying infrastructure, including servers, storage, networking, operating systems, middleware, and the application runtime itself. Upgrades, security patches, and capacity scaling are applied server-side with no action required from the tenant. Multi-tenancy is a defining architectural trait: a single instance of the software serves many customer accounts (tenants) with data isolation enforced in the application layer or database schema. This lets the provider deliver uniform updates and achieve economies of scale.
SaaS sits at the top of the cloud services stack (IaaS -> PaaS -> SaaS). It is distinguished from on-premises software because the customer bears zero ownership or operational responsibility for the underlying systems. Common examples include Salesforce (CRM), Google Workspace (productivity), Slack (collaboration), and Zoom (communications). The model also extends to infrastructure SaaS products accessible only via API, such as Stripe (payments) or Twilio (communications).
Key facts
- SaaS customers access software over the internet; no local installation is required.
- The provider manages the entire stack: hardware, OS, runtime, and application.
- Multi-tenancy allows a single app instance to serve many customers securely.
- Pricing is typically subscription-based (monthly/yearly) or usage-based.
- SaaS is the top layer of cloud services, above IaaS and PaaS.
How it works in practice
Related terms
References
More in Cloud Computing
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