I already posted this question about API calls or endpoints, on Stack Overflow, however, it was marked as off-topic.
So where should I post such questions where answers can be expected from users who are already aware or have tried their hands at this?
You're asking how to perform a specific function within the ebay-api. In turn, you're asking how to use the ebay-api. For that reason, I would still say Stack Overflow. In fact, they have an explicit ebay-api tag, which you have used in your question.
What your question fails to convey is that you're asking how to use the API. It actually reads like your asking for a recommendation of an API, given a set requirement of needing to be able to draw out specific data. Granted, careful reading makes it clear that your asking for help with the API, but I cannot help but understand why users would gloss over it, and interpret it as a recommendation question.
I am suggesting an edit to your question, which I believe will make it clearer what you're actually asking. At that point, I believe you should ask about your question being closed as off-topic on the Stack Overflow Meta.
With the question edited, and the meta question posted, further feedback has been requested. What I am about to say is mostly my opinion, unpopular as it may be.
Firstly, It was my suggestion that you ask about your question being closed as off-topic. It was not my suggestion that you ask for your question to be reopened. The key difference, here, is that you should be asking for further feedback. You should not be immediately jumping to the conclusion that your question is on-topic, and should be reopened.
This brings me to my personal opinion; realistically, Stack Overflow is the last place you should be asking your question. It is still the best place to ask your question, on the Stack Exchange network; but not all questions are fit for the Stack Exchange network. The thing is, there is a great debate on the decline of Stack Overflow. In my personal opinion, users are far less helpful, and far more elitist; especially in comparison to the many other stack sites. I have even seen stack sites that acknowledge this, by loosening their rules simply so that fewer users were told that Stack Overflow was the better option for their question.
Ultimately, you have been told that your question is off-topic because it shows no research effort, and still asks for a recommendation. This is despite the fact that "shows no research effort" is a hard written reason for downvotes, but not close votes. This is despite the fact that you show several references to documents you have viewed over (and the amount of effort is insignificant to debate, as "none" is always significantly less than "some"). This is despite the fact that we have edited your question to highlight the fact that you are already using a very specific API, and are asking for help with a very specific function of this very specific API.
At the end of the day, Stack Overflow is the best Stack Exchange site for your question; but they do not want it. There really is not much more you can do, I am afraid. I personally steer clear of Stack Overflow for this very reason. All that said, there appears to be an eBay Developers Forum. This might be a good avenue for seeking help, in regards to the eBay API.
