As you've discovered there are a number of different APIs, with some commonalities and many differences. The SasS environment has a whole new set of APIs as well.
There is a REST api for the QRS (Repository Service) with a getting started doc here
https://help.qlik.com/en-US/sense-developer/August2021/Subsystems/RepositoryServiceAPI/Content/Sense...
QRS provides management and metadata.
You mentioned engima, which is a different beast altogether. Enigma is a wrapper for the engine api. The engine api provides access to the applications and the data and objects within those applications. There is no native REST interface for the engine/enigma api for QSE (Qlik Sense Enterprise).
A proxy is the web front end that specifies user authentication and routing. The proxy name is specified as the first path element in the url, or the default proxy if not specified. The Admin can define multiple virtual proxies (paths) to support different auth methods (and routing). For example
https://myserver -- use the default proxy, which may use Windows auth
https://myserver/foo -- use the "foo" proxy, which is defined to use SAML
The proxy's primary function is to support user browser access. When using an API for programmatic P2P work, some APIs let you bypass the proxy and go directly to a service port to make the API calls. For QRS, the port is 4242. In that case, you must use a certificate to prove you are authorized to use the port interface.
What kind of data or function is your goal? I ask to be able to direct you to the correct API and possible further resources.
There is also a qlikdeveloper slack channel which is a good resource.
-Rob
http://masterssummit.com
http://qlikviewcookbook.com
http://www.easyqlik.com
