SaaS

A software delivery and business model where customers use a centrally operated service, usually through a subscription.

Why it matters

SaaS gives teams a shared model for decisions that otherwise become implicit. It helps clarify constraints, expected outcomes, and the trade-offs that appear as products and systems evolve.

Mental model

Treat SaaS as a context for making choices rather than a single implementation technique. Ask what assumptions are being made, which risks are acceptable, and how success will be measured.

Practical considerations

• Make goals and constraints explicit.
• Separate reversible experiments from durable commitments.
• Review operational, product, security, and organizational consequences.
• Record important decisions and revisit them when assumptions change.

Common mistakes

• Applying the label without changing decision-making.
• Ignoring lifecycle and ownership costs.
• Optimizing for initial speed while hiding long-term constraints.

Single-tenant SaaS

A SaaS architecture where each customer has a dedicated application or data environment.

Multi-tenant SaaS

A SaaS architecture where multiple customers share infrastructure while their data and access remain logically isolated.