You can now use Amazon WorkSpaces APIs to register your directories with WorkSpaces and to modify directory details. The new APIs enable you to automate your workflows that require registering a directory with WorkSpaces or modifying directory level WorkSpaces properties including default WorkSpace creation settings, self-service permissions, and access controls.

from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/11/amazon-workspaces-introduces-workspaces-directory-apis/