Whether the API is REST is irrelevant. In most big data use-cases on real systems, you have special dump/export tools to get your data out. In this case, the qu

Whether the API is REST is irrelevant. In most big data use-cases on real systems, you have special dump/export tools to get your data out. In this case, the question is whether such a tool/API exists, how fast and practical it is. It can be simple though, eg. do they have a button on the webconsole that exports your dataset to a CSV file that you can then download per FTP.