Most ISV partners arrive at multi-tenancy with prior SaaS experience. The principles transfer — one application, many customers, strict isolation, costs that scale slower than revenue. What doesn't transfer cleanly is the structural vocabulary: provider and consumer subaccounts, HDI containers, the SaaS Provisioning Service, and what actually happens when a customer clicks “subscribe.”
This post covers the account topology you commit to before writing production code, the three data isolation strategies and when each applies, and the tenant lifecycle events — onboarding, upgrade, offboarding — that separate a well-designed SaaS from one that works at five customers and breaks at fifty.
