The AWS SDK for JavaScript v2 has reached end-of-support. We recommend that you migrate to [AWS SDK for JavaScript v3](https://docs.aws.amazon.com//sdk-for-javascript/v3/developer-guide/). For additional details and information on how to migrate, please refer to this [announcement](https://aws.amazon.com/blogs//developer/announcing-end-of-support-for-aws-sdk-for-javascript-v2/).

# Working with Services in the SDK for JavaScript
<a name="working-with-services"></a>

The AWS SDK for JavaScript provides access to services that it supports through a collection of client classes. From these client classes, you create service interface objects, commonly called *service objects*. Each supported AWS service has one or more client classes that offer low-level APIs for using service features and resources. For example, Amazon DynamoDB APIs are available through the `AWS.DynamoDB` class.

The services exposed through the SDK for JavaScript follow the request-response pattern to exchange messages with calling applications. In this pattern, the code invoking a service submits an HTTP/HTTPS request to an endpoint for the service. The request contains parameters needed to successfully invoke the specific feature being called. The service that is invoked generates a response that is sent back to the requestor. The response contains data if the operation was successful or error information if the operation was unsuccessful. 

![The AWS request response service pattern.](http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/images/request-response.png)


Invoking an AWS service includes the full request and response lifecycle of an operation on a service object, including any retries that are attempted. A request is encapsulated in the SDK by the `AWS.Request` object. The response is encapsulated in the SDK by the `AWS.Response` object, which is provided to the requestor through one of several techniques, such as a callback function or a JavaScript promise.

**Topics**
+ [Creating and Calling Service Objects](creating-and-calling-service-objects.md)
+ [Logging AWS SDK for JavaScript Calls](logging-sdk-calls.md)
+ [Calling Services Asychronously](calling-services-asynchronously.md)
+ [Using the Response Object](the-response-object.md)
+ [Working with JSON](working-with-json.md)
+ [Retry strategy in the AWS SDK for JavaScript v2](retry-strategy.md)