Still not sure where and how you want to call the action, but perhaps you can use an action input parameter of type Properties.
The keys would be the names of the data properties you want to pass, and the values would be the actual values of these properties. Something like the following:
var props = new Properties(); props.put("endpointUsername", "myusername"); props.put("endpointPassword", "mysecret"); props.put("apiUrl", "https://someurl/address"); props.put("authKey", "key-0123456789"); // then pass props object as an input to your action