Computing environments are scalably generated and provisioned based on metadata associated with separately defined containers of groups of sandboxes. Each container of a group of sandboxes is its own digital construct and is wrapped with metadata that defines the nature and aspects of the grouping, including enumerating individual members of a team, factors or attributes of assignments, and the like. The metadata, therefore, identifies the sandboxes to generate and, within those sandboxes, the computing environments to generate and how such computing environments are to be provisioned. In variable team settings quantities and identities of individuals can be unknown and can dynamically change. Administrators provide team definitions without rosters, or with rosters that comprise only previously registered individuals. Subsequently joining individuals are dynamically added to the roster and appropriate sandboxes and computing environments are generated at a different time than the sandboxes and computing environments were generated for other users.