API calls cannot have deterministic progress calculated in advance due to various factors like current system resources available, load, amount of data stored a

API calls cannot have deterministic progress calculated in advance due to various factors like current system resources available, load, amount of data stored and various other things that can impact the time it takes to finish an API call. So I don't see how you can get a progress percentage out of such call. Spinners are the only way as of now. It is not always like a File upload where you know the size of the file and the chunks uploaded to the server already.