All API requests are sent in the format of GET or POST. For GET requests, all parameters are path parameter; for POST requests, all parameters are sent in the POST body and in JSON format.
All returns are in JSON format.
For the Market Data interface, there are "code" and "message" fields that represent the request status and attributes on the top layer of JSON, and the actual return content is in the "data" field. (The K-line data interface has no code and message yet.)