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

Common request parameters

Parameter Type Required Description
Format String No The response format. Valid values:
  • JSON (default)
  • XML
Version String Yes The version number of the API. The parameter value is in the YYYY-MM-DD format. Set the value to 2015-04-01.
Signature String Yes The signature string of the current request. For more information, see Request signatures.
SignatureMethod String Yes The encryption method of the signature string. Set the value to HMAC-SHA1.
SignatureNonce String Yes A unique, random number used to prevent replay attacks. You must use different numbers for different requests.
SignatureVersion String Yes The version of the signature encryption algorithm. Set the value to 1.0.
AccessKeyId String Yes The AccessKey ID provided to you by Alibaba Cloud.
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 2013-01-10T12:00:00Z to indicate January 10, 2013, 20:00:00 (UTC+8).

Sample requests:

https://sts.aliyuncs.com?Action=AssumeRole
&Format=xml
&Version=2015-04-01
&Signature=Pc5WB8gokVn0xfeu%2FZV%2BiNM1dg****
&SignatureMethod=HMAC-SHA1
&SignatureNonce=1521552885****
&SignatureVersion=1.0
&AccessKeyId=LTAI4GENiH2u8MVj7Khh****
&Timestamp=2015-06-01T12:00:00Z

Common response parameters

API responses use the HTTP response format. 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. Every response returns a unique RequestID regardless of whether the call is successful.
  • A 2xx status code indicates a successful call.
  • A 4xx or 5xx status code indicates a failed call.
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*/
    }