This topic describes the request and response parameters that are included in all API operations.

Common request parameters

Table 1. Parameters
FormatStringNoThe format in which to return the response. Valid values:
  • JSON (default)
  • XML
VersionStringYesThe version number of the API. Specify the version number in the YYYY-MM-DD format. Valid values:


AccessKeyIdStringYesThe AccessKey ID provided to you by Alibaba Cloud.
SignatureStringYesThe signature string of the request.
SignatureMethodStringYesThe encryption method of the signature string. Set the value to


TimestampStringYesThe 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, you can set the value to 2013-01-10T12:00:00Z. This value indicates 20:00:00 on January 10, 2013 (UTC+8).

SignatureVersionStringYesThe version of the signature encryption algorithm. Set the value to


SignatureNonceStringYesA unique random number that is used to prevent replay attacks.

You must use a unique random number for each request.

ResourceOwnerAccountStringNoThe Alibaba Cloud account to which the resource you want to access belongs.

Common response parameters

API responses use the HTTP response format. A response can be returned in the JSON or XML format. You can specify the response format in the request. The default response format is XML. Every response returns a unique RequestId regardless of whether the call is successful.
  • A 2xx HTTP status code indicates a successful call.
  • A 4xx or 5xx HTTP status code indicates a failed call.
Sample responses
  • XML format
    <?xml version="1.0" encoding="utf-8"?> 
        <!--Result Root Node-->
        <Interface Name+Response>
            <!--Returned Request Tag-->
            <!--Returned Result Data-->
        </Interface Name+Response>
  • JSON format
        /*Returned Result Data*/