Well you can't.
The one mechanism that could lock that service down with something that could not just be picked up on the network tab and restrict access to the service to only those people you decide does exist. It's called Authentication, and you're ruling that out.
If you think this through; if not authentication, what would you lock down the service ...
When using the JSS Integrated Mode on a project, I've seen that the conversion of the JSON to HTML takes time. This depends on how big the JSON response is.
What I did
I had to extend the GetJsLayoutRenderer in order to be able to change the instantiation of the class JsLayoutRenderer.
The main drawback with this is that if you have dynamic ...
This error happens because Sitecore is trying to load that assembly since it's being referenced either through the web.config or the dll itself has dependencies within it which are not loaded.
If you think about what the error message says: It has a reference to an assembly and it can't load it.
In cases like this what you have to do is find where the ...