There are two major differences between QAP and QES. The first is a commercial difference, QAP is not licensed through the normal tokens but can be licensed for CPU cores.
The second difference is that since QAP is intended for using our APIs to deploy custom solutions the Qlik Sense client is disabled in QAP.
It's the same installation package as QES but applying a QAP license key will disable /hub
All the normal APIs are available as well as connectors and authentication. Right now you would have to build your loadscript in Qlik Sense Desktop, or via programming, and import the app to QAP. This is something we intend to change in the future.
Typical use-case is that you want to deploy some analytical features to an external audience.