SaaS delivers continuously operated software through a browser or API. The provider manages releases, uptime, security, support, and infrastructure. A typical system includes a client, API, identity layer, domain services, database, background workers, integrations, billing, and observability.

How to apply it

Identify the buyer, user, core job, measurable outcome, and recurring value. Multi-tenancy allows organizations to share infrastructure, but every operation must preserve customer data boundaries.

Worked example

A project SaaS lets an organization invite teammates, create projects, and pay monthly. The provider deploys updates centrally while enforcing organization-specific access.

Common mistakes to avoid

Treating SaaS as only a website plus recurring payment; ignoring support, export, uptime, security, and cancellation.

Practice task

Implement this concept in the capstone. Add one positive test, one negative or failure-path test, and a short note explaining the trade-off you chose.