Quick answer
Software as a service (SaaS) is software delivered over the internet on a subscription basis. Salesforce, Slack and WebGrow24 are SaaS.
What it is
SaaS is a software delivery model where the vendor hosts the application and customers access it over the internet. Customers pay a recurring fee instead of buying a license. SaaS is multi-tenant: one codebase serves many customers.
Why it matters
SaaS is the dominant software model for new products. It changes how you build (multi-tenant, billing, observability) and how you sell (land and expand, MRR, NRR).
How to use it
- Design multi-tenant from day one.
- Integrate subscription billing with Stripe or Paddle.
- Build product analytics for activation, retention and expansion.
- Set up SSO and audit logs for enterprise readiness.
Examples
- Salesforce, Slack, Notion, Figma, Linear and WebGrow24 are SaaS.