Amazon CloudWatch
API Reference (API Version 2010-08-01)

Making API Requests

Query requests used with Amazon CloudWatch are HTTP or HTTPS requests that use the HTTP verb GET or POST and a Query parameter named Action or Operation. This documentation uses Action, although Operation is supported for backward compatibility.

Amazon CloudWatch Endpoints

An endpoint is a URL that serves as an entry point for a web service. You can select a regional endpoint when you make your requests to reduce latency. For information about the endpoints used with CloudWatch, see Regions and Endpoints in the Amazon Web Services General Reference.

Query Parameters

Each query request must include some common parameters to handle authentication and selection of an action. For more information, see Common Parameters.

Some API operations take lists of parameters. These lists are specified using the following notation: param.member.n. Values of n are integers starting from 1. All lists of parameters must follow this notation, including lists that contain only one parameter. For example, a Query parameter list looks like this:

&attribute.member.1=this &attribute.member.2=that

Request Identifiers

In every response from an AWS Query API, there is a ResponseMetadata element, which contains a RequestId element. This string is a unique identifier that AWS assigns to provide tracking information. Although RequestId is included as part of every response, it is not listed on the individual API documentation pages to improve readability and to reduce redundancy.

Query API Authentication

You can send query requests over either HTTP or HTTPS. Regardless of which protocol you use, you must include a signature in every query request. For more information about creating and including a signature, see Signing AWS API Requests in the Amazon Web Services General Reference.

Available Libraries

AWS provides libraries, sample code, tutorials, and other resources for software developers who prefer to build applications using language-specific APIs instead of the command-line tools and Query API. These libraries provide basic functions (not included in the APIs), such as request authentication, request retries, and error handling so that it is easier to get started. Libraries and resources are available for the following languages and platforms:

For libraries and sample code in all languages, see Sample Code & Libraries.

Making API Requests Using the POST Method

If you don't use one of the AWS SDKs, you can make CloudWatch API requests over HTTP using the POST request method. The POST method requires you to specify the operation in the header of the request and provide the data for the operation in JSON format in the body of the request.

Header name Header value

The Amazon CloudWatch endpoint. For example,


You must provide the time stamp in either the HTTP Date header or the AWS x-amz-date header. Some HTTP client libraries don't let you set the Date header. When an x-amz-date header is present, the system ignores any Date header during the request authentication.

The x-amz-date header must be specified in ISO 8601 basic format. For example: 20130315T092054Z


The set of authorization parameters that AWS uses to ensure the validity and authenticity of the request. For more information about constructing this header, see Signature Version 4 Signing Process in the Amazon Web Services General Reference.


Specifies the CloudWatch operation:


For example, for GetMetricData the target value is the following:



Specifies the input format. The valid value is application/json


Specifies the response format. The valid value is application/json


Size of the payload in bytes.


Specifies the encoding format of the input and output. The valid value is amz-1.0

The following is an example header for an HTTP request to return metric data in JSON format:

POST / HTTP/1.1 host: x-amz-target: GraniteServiceVersion20100801.GetMetricData x-amz-date: 20180112T092034Z Authorization: AWS4-HMAC-SHA256 Credential=REDACTEDREDACTED/20180411/us-east-1/monitoring/aws4_request, SignedHeaders=content-encoding;content-length;content-type;host;x-amz-date;x-amz-target, Signature=e945ed75cb91f88f138445fba02d3af93d96bfd8491e5d03588ae1b65188ff1d Content-Type: application/json Accept: application/json Content-Encoding: amz-1.0 Content-Length: 45 Connection: keep-alive