Identity Platform Migration to AWS

Atlassian's Identity Platform, responsible for authentication, user management, and product authorization, has undergone a significant architectural evolution. This includes migrating from on-premises data centers to AWS, transitioning from a single-tenant to a multi-tenanted architecture, and decomposing a monolithic User Management service into smaller, multi-tenanted services. The platform has adopted guiding principles for feature development and API exposure, and utilizes EventStorming for shared understanding. Decomposition strategies include vertical and horizontal slicing, prioritizing functionality, and migrating business logic before domain models.