I'd like to see a single example of APIFunction deployed that is accessible via curl, not a web browser.
For example:
func = APIFunction[{"x" -> "Integer"}, FactorInteger[#x] &];
URLFetch["https://www.wolframcloud.com/objects/66b35b10-0f8e-4be4-bbdc-7ee3f6fbf82a", "Parameters" -> {"x" -> "1"}]
gives
Api's are not generally meant to be used by logging in and manipulating elements in a web page. I"m sure this is possible and I'm just missing something.
URLFetch
like that it cannot know who you are. That HTML is probably for the login form. $\endgroup$