# Basic Information

• baseurl https://openapi.bitstan.trade
• All endpoints return either a JSON object or array.
• Data is returned in Reverse order. newest first, oldest last.
• All time and timestamp related fields are in milliseconds.

• HTTP 4XX return codes are used for malformed requests; the issue is on the sender's side.
• HTTP 429 return code is used when breaking a request rate limit.
• HTTP 418 return code is used when an IP has been auto-banned for continuing to send requests after receiving 429 codes.
• HTTP 5XX return codes are used for internal errors
• HTTP 504 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.
• All endpoints can possibly return an ERROR, the error payload is as follows:

{
  "code": -1121,
  "msg": "Invalid symbol."
}

• All requests are based on the Https protocol, and the Content-Type in the request header information needs to be uniformly set to:'application/json'
• For the interface of the GET method, the parameters must be sent in the query string
• The interface of the POST method, the parameters must be sent in the request body
• Parameters may be sent in any order.

• There will be a limited frequency description below each interface.
• A 429 will be returned when either rate limit is violated.

• Each endpoint has a security type that determines how you will interact with it.
• API-keys are passed into the Rest API via the X-CH-APIKEY header.
• API-keys and secret-keys are case sensitive.

• When calling the TRADE or USER_DATA interface, the signature parameter should be passed in the X-CH-SIGN field in the HTTP header.
• The signature uses the HMAC SHA256 algorithm. The API-Secret corresponding to the API-KEY is used as the HMAC SHA256 key.
• The request header of X-CH-SIGN is based on timestamp + method + requestPath + body string (+ means string connection) as the operation object
• The value of timestamp is the same as the X-CH-TS request header, method is the request method, and the letters are all uppercase: GET/POST
• requestPath is the request interface path For example: /sapi/v1/order
• body is the string of the request body (post only)
• The signature is not case sensitive.

• The signature interface needs to pass the timestamp in the X-CH-TS field in the HTTP header, and its value should be the unix timestamp of the request sending time e.g. 1528394129373
• An additional parameter, recvWindow, 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.
• In addition, if the server calculates that the client's timestamp is more than one second ‘in the future’ of the server’s time, it will also reject the request.
• The logic is as follows:

if (timestamp < (serverTime + 1000) && (serverTime - timestamp) <= recvWindow) {
  // process request
} else {
  // reject request
}

Serious trading is about timing. Networks can be unstable and unreliable, which can lead to requests taking varying amounts of time to reach the servers. With 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!

Here is a step-by-step example of how to send a vaild signed payload from the Linux command line using echo, openssl and curl.

• body:

{"symbol":"BTCUSDT","price":"9300","volume":"1","side":"BUY","type":"LIMIT"}

• HMAC SHA256 Signature:

[linux]$ echo -n "1588591856950POST/sapi/v1/order/test{\"symbol\":\"BTCUSDT\",\"price\":\"9300\",\"volume\":\"1\",\"side\":\"BUY\",\"type\":\"LIMIT\"}" | openssl dgst -sha256 -hmac "902ae3cb34ecee2779aa4d3e1d226686"
(stdin)= c50d0a74bb9427a9a03933d0eded03af9bf50115dc5b706882a4fcf07a26b761

• Curl command:

(HMAC SHA256)
[linux]$ curl -H "X-CH-APIKEY: c3b165fd5218cdd2c2874c65da468b1e" -H "X-CH-SIGN: c50d0a74bb9427a9a03933d0eded03af9bf50115dc5b706882a4fcf07a26b761" -H "X-CH-TS: 1588591856950" -H "Content-Type:application/json" -X POST 'http://localhost:30000/sapi/v1/order/test' -d '{"symbol":"BTCUSDT","price":"9300","quantity":"1","side":"BUY","type":"LIMIT"}'