Adopting a SaaS model is no trivial effort. Wandering into the universe of multi-tenancy means tackling a broad range of new architectural challenges. How do you automate the onboarding and provisioning of new tenants? How do you secure a shared multi-tenant infrastructure and prevent any flavor of cross-tenant access? How do you effectively partition tenant data? These are amongst a core set SaaS architecture topics in this chalk which is aimed at equipping SaaS newcomers with a clear view of some of the best practices associated with delivering SaaS solutions on AWS. The goal here is to explore and discuss fundamental architectural strategies of SaaS and highlight key considerations that will shape the security, agility, and success of your SaaS applications.