Either by design or coincidence APEX is an incredible fit as the product for cloud based-systems from development to deployment. From a development perspective, APEX is a cloud development platform as all development is done in a web browser. There are absolutely no development components to be installed on a client machine. All components can that are developed in APEX can be exposed as web services and be consumed by other applications running on a private, public or hybrid cloud. All the end user needs to access the application is a URL. From a deployment perspective, APEX addresses some of the biggest issues with public cloud application deployments: dynamic multi-tenant workload migration, management and provisioning. This is because the APEX security, database, metadata, and application are all contained in the Oracle Database. This means an APEX application from bits on disk, to network, to database to the application can be managed, provisioned and migrated as one workload. This type of end to end workload management, migration and provisioning can only be achieved by using virtualization. With Oracle APEX, all these capabilities are provided without the need and overhead of a virtual server.
More on APEX in the cloud can be found here: