https://openapi.lyotrade.com4XX return codes are used for malformed requests; the issue is on the sender's side.429 return code is used when breaking a request rate limit.418 return code is used when an IP has been auto-banned for continuing to send requests after receiving 429 codes.5XX return codes are used for internal errors504 return code is used when the API successfully sent the message but not get a response within the timeout period. It is important to NOT treat this as a failure operation; the execution status is UNKNOWN and could have been a success.Content-Type in the request header information needs to be uniformly set to:'application/json'GET method, the parameters must be sent in the query stringPOST method, the parameters must be sent in the request bodyX-CH-APIKEY header.TRADE or USER_DATA interface, the signature parameter should be passed in the X-CH-SIGN field in the HTTP header.HMAC SHA256 algorithm. The API-Secret corresponding to the API-KEY is used as the HMAC SHA256 key.X-CH-SIGN is based on timestamp + method + requestPath + body string (+ means string connection) as the operation objecttimestamp is the same as the X-CH-TS request header, method is the request method, and the letters are all uppercase: GET/POSTrequestPath is the request interface path For example: /sapi/v1/orderbody is the string of the request body (post only)X-CH-TS field in the HTTP header, and its value should be the unix timestamp of the request sending time e.g. 1528394129373recvWindow, may be sent to specify the number of milliseconds after timestamp the request is valid for. If recvWindow is not sent, it defaults to 5000.recvWindow, you can specify that the request must be processed within a certain number of milliseconds or be rejected by the server.It recommended to use a small recvWindow of 5000 or less!echo, openssl, and curl.KeyValueapiKeyvmPUZE6mv9SD5V5e14y7Ju91duEh8AsecretKey902ae3cb34ecee2779aa4d3e1d226686ParametervaluesymbolBTCUSDTsideBUYtypeLIMITvolume1price9300