Amazon AWS SDK User Manual

Making Requests
Asynchronous Callbacks
All requests made through the SDK are asynchronous and use a callback interface. Each service method
that kicks off a request can accept a callback as the last parameter with the signature function(error,
data) { ... }.This callback will be called when the response or error data is available.
For example, the following service method can be called with a standard callback to retrieve the response
data or error:
new AWS.EC2().client.describeInstances(function(error, data) {
if (error) {
console.log(error); // an error occurred
} else {
console.log(data); // request succeeded
}
});
The error and data parameters are described in the Response Object section below.
Note that if you do not specify a callback, the operation will return an AWS.Request object that must be
manually sent using the send() method:
// create the AWS.Request object
var request = new AWS.EC2().client.describeInstances();
// register a callback to report on the data
request.on('success', function(resp) {
console.log(response.data); // log the successful data response
});
// send the request
request.send();
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AWS SDK for Node.js Getting Started Guide
Asynchronous Callbacks

Amazon AWS SDK Specifications

General

Category	Software Development Kit (SDK)
Developer	Amazon Web Services (AWS)
License	Apache License 2.0
Purpose	To enable developers to interact with AWS services from their applications.
Supported Languages	Java, Python, JavaScript, .NET, Ruby, PHP, Go, C++
Supported AWS Services	All AWS services
Operating Systems	Windows, macOS, Linux
Latest Version	Varies by SDK and language. Refer to the official AWS documentation for the specific SDK.
Repository	GitHub (for many SDKs)
Documentation	Available on the AWS website.
SDK Features	API abstraction, request signing, error handling, retry logic, data serialization, and support for various authentication methods.