This topic describes the common request and response parameters.

Common request parameters

Common request parameters must be included in all API requests.

Table 1. Common request parameters
Name Type Required Description
Format String No The format in which to return the response. Valid values:

JSON and XML. Default value: JSON.

Version String Yes The version number of the API. Format: YYYY-MM-DD. Set the value to


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


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, 2013-01-10T12:00:00Z specifies 20:00:00 on January 10, 2013 (UTC+8).

SignatureVersion String Yes The version of the signature encryption algorithm. Set the value to


SignatureNonce String Yes A unique and random number that is used to prevent replay attacks.

You must use different random numbers for different requests.

Common response parameters

API responses use the HTTP response format. A 2XX status code indicates a successful call. A 4XX or 5XX status code indicates a failed call. Responses can be returned in JSON or XML format. The default response format is JSON. You can specify the format in requests.

Every response returns a unique RequestID regardless of whether the call is successful.
  • XML format
    <? xml version="1.0" encoding="utf-8"? > 
        <!--Root node of the response-->
        <Operation name+Response>
            <!--Return request tag-->
            <!--Response result data-->
        </Operation name+Response>
  • JSON format
        /*Response result data*/