This topic describes the parameters that are common to all API requests and responses.

Common request parameters

Parameter Type Required Description
Action String Yes The operation that you want to perform.
Format String No The response format. Valid values:
  • JSON
  • XML
Default value: JSON.
Version String Yes The version number of the API. The value must be in the YYYY-MM-DD format. Set the value to 2020-06-30.
AccessKeyId String Yes The AccessKey ID provided to you by Alibaba Cloud.
Signature String Yes The signature string of the current request.
SignatureMethod String Yes The encryption method of the signature string. Set the value to HMAC-SHA1.
Timestamp String Yes The timestamp of the request. Specify the time in the ISO 8601 standard in the YYYY-MM-DDThh:mm:ssZ format. The time must be in UTC.

For example, use 2020-06-30T20:00:00Z to indicate June 30, 2020, 20:00:00 (UTC+8).

SignatureVersion String Yes The version of the signature encryption algorithm. Set the value to 1.0.
SignatureNonce String Yes A unique, random number used to prevent replay attacks.

You must use different numbers for different requests.

ResourceOwnerAccount String No The Alibaba Cloud account to which the resource you want to access belongs.
Sample requests 
https://cas.aliyuncs.com/?Action=<APIName>
?Format=xml
&Version=2020-06-30
&AccessKeyId=key-****
&Signature=Pc5WB8gokVn0xfeu%2FZV%2BiNM1dg****
&SignatureMethod=HMAC-SHA1
&Timestamp=2020-06-30T20:00:00Z
&SignatureVersion=1.0
&SignatureNonce=15215528852396
&ResourceOwnerAccount=123456****

Common response parameters

API responses use the HTTP response format where a 2xx status code indicates a successful call and a 4xx or 5xx status code indicates a failed call. Every response returns a unique RequestID regardless of whether the call is successful. The RequestId parameter indicates the ID of the request.

Responses can be returned in either the JSON or XML format. You can specify the response format in the request. The default response format is JSON.

Sample responses
  • XML format 
    <?xml version="1.0" encoding="utf-8"?> 
    <!--Result Root Node-->
    <Interface Name+Response>
        <!--Return Request Tag-->
        <RequestId>4C467B38-3910-447D-87BC-AC049166F216</RequestId>
        <!--Return Result Data-->
    </Interface Name+Response>
  • JSON format 
    {
    "RequestId":"4C467B38-3910-447D-87BC-AC049166F216",
    /*Return Result Data*/
    }