Application integration APIs
Having now discussed ways in which the platform exposes standard APIs to your application and its data, this section describes ways in which you can expose the business logic functionality that is encapsulated within your application’s Service layer. First, we will cover ways in which you can build and expose an Apex API for use by Developer X when they are also using Apex, and then we will discuss exposing application APIs for REST for cases when Developer X is using languages other than Apex.
In some cases, Developer X can achieve such functionality through the standard Salesforce APIs. However, depending on the requirements, it might be easier and safer to call an API that exposes existing business logic within an application. You can decide to do this for the same reason you would create a custom UI rather than expect the end users to solely utilize the standard UI (because using your objects directly requires them to understand the...