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Public parameters

Last Updated: Jan 29, 2018

Public request parameters are the request parameters used in each API.

Description of relevant parameters

NameTypeRequired or notDescription
FormatStringYesType of the return value. JSON and XML formats are supported. The default value is XML.
VersionStringYesAPI version number, in the format of YYYY-MM-DD. The current version is 2015-12-01.
AccessKeyIdStringYesYour AccessKey ID issued by Alibaba Cloud.
SignatureStringYesSignature result string. For more information about the signature calculation method, see the signature mechanism description.
SignatureMethodStringYesSignature method. Currently, HMAC-SHA1 is supported.
TimestampStringYesRequest time stamp. The date format follows the ISO8601 standard and uses the UTC time.
Format: YYYY-MM-DDThh:mm:ssZ. For example, 2016-01-01T12:00:00Z (20:00:00, January 1, 2016, Beijing time).
SignatureVersionStringYesSignature algorithm version. The current version is 1.0.
SignatureNonceStringYesUnique random number, which is used to prevent network replay attacks. You must use different random numbers for different requests.


  1. https://
  2. ?Format=json
  3. &Version=2015-12-01
  4. &Signature=Pc5WB8gokVn0xfeu%2FZV%2BiNM1dgI%3D
  5. &SignatureMethod=HMAC-SHA1
  6. &SignatureNonce=15215528852396
  7. &SignatureVersion=1.0
  8. &AccessKeyId=key-test
  9. &Timestamp=2016-01-01T12:00:00Z

Public response parameters

The system returns a unique identification code (RequestId) each time you send a request to call an interface, no matter whether the call succeeds or not.


  1. <?xml version="1.0" encoding="utf-8"?>
  2. <!—Result root node-->
  3. <Interface name + Response>
  4. <!—Return request tag-->
  5. <RequestId>4C4fdsf38-3910-447D-87AD-AC078932216</RequestId>
  6. <!—Return result data-->
  7. </Interface name + Response>

Return results

After an API is called, data is returned in a unified format. The returned HTTP status code 2xx indicates that the call is successful. The returned HTTP status code 4xx or 5xx indicates that the call fails. For a successful call, the primary formats of returned data are XML and JSON. When a request is sent, an external system can input parameters to specify the format of returned data. The default format is XML.

Note: In this document, examples of return results are formatted for viewing convenience. The actual returned results have no line breaks, indentation, or other layouts.

Successful results

XML results returned include a message stating if the request is successful and the specific service data. An example is as follows:

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <!—Result root node-->
  3. <Interface name + Response>
  4. <!—Return request tag-->
  5. <RequestId>4C4fdsf38-3910-447D-87AD-AC078932216</RequestId>
  6. <!—Return result data-->
  7. </Interface name + Response>

JSON example

  1. {
  2. "RequestId": "4C4fdsf38-3910-447D-87AD-AC078932216",
  3. /* Return result data*/
  4. }

Error results

After an error is reported in an API call, no result data is returned. The caller can refer to the table in the appendix Error Code Table to locate the cause of the error. When an error occurs in a call, an HTTP status code 4xx or 5xx is returned for the HTTP request. The returned message body contains the specific error code and error message. The message body also contains the globally unique RequestId and the requested HostId.

If the caller cannot identify the cause of the error, the caller can contact Alibaba Cloud Customer Service and provide the HostId and RequestId to help us solve the problem as quickly as possible.

An example is as follows:

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <Error>
  3. <RequestId>8906582E-6722-409A-A6C4-0E7863B733A5</RequestId>
  4. <HostId></HostId>
  5. <Code>UnsupportedOperation</Code>
  6. <Message>The specified action is not supported.</Message>
  7. </Error>

JSON example

  1. {
  2. "RequestId": "7463B73D-35CC-4D19-A010-6B8D65D242EF",
  3. "HostId": "",
  4. "Code": "UnsupportedOperation",
  5. "Message": "The specified action is not supported."
  6. }