This image shows the recommended architecture for low-code app development and deployment with Oracle APEX Application Development (APEX Service) and all Oracle Autonomous Database services.

The image comprises an Oracle Cloud Infrastructure region and services/users external that region.

The region contains a single availability domain and a virtual cloud network (VCN) that spans the availability domain. This VCN contains a public subnet and a private subnet, which both span the availability domain.

• The pubic subnet contains an API gateway and a load balancer. Access to the subnet is controlled by a security list and a route table.
• The private subnet contains an autonomous database, which consists of a APEX application and an instance of Oracle REST Data Services (ORDS). Access to the subnet is controlled by a security list and a route table.

A remote user, external to the region communicated bidirectionally with the public internet, which exchanges traffic between itself and, through an internet gateway, the API gateway inside the VCN's public subnet. The API gateway then directs traffic to the load balancer, which communicates bidirectionally with the Oracle REST Data Services in the VCN's private subnet. The remote user can also with the load balancer, also through the internet gateway.

Also external to the region, external REST APIs Oracle communicate bidirectionally through a NAT gateway with the APEX application in the private subnet's Autonomous Database.