AWS Cloud9 is no longer available to new customers. Existing customers of AWS Cloud9 can continue to use the service as normal. [Learn more](https://aws.amazon.com/blogs/devops/how-to-migrate-from-aws-cloud9-to-aws-ide-toolkits-or-aws-cloudshell/)

# Working with AWS CDK in the AWS Cloud9 IDE
<a name="cdk-explorer"></a>

The **AWS CDK service** enables you to work with [AWS Cloud Development Kit (AWS CDK)](https://aws.amazon.com/cdk/) applications, or *apps*. You can find detailed information about the AWS CDK in the [AWS Cloud Development Kit (AWS CDK) Developer Guide](https://docs.aws.amazon.com/cdk/latest/guide/). 

AWS CDK apps are composed of building blocks known as *[constructs](https://docs.aws.amazon.com/cdk/latest/guide/constructs.html)*. These building blocks include definitions for your CloudFormation stacks and the AWS resources within them. Using the **AWS CDK Explorer**, you can see the [stacks](https://docs.aws.amazon.com/cdk/latest/guide/stacks.html) and [resources](https://docs.aws.amazon.com/cdk/latest/guide/resources.html) that are defined in AWS CDK *tree view*. You can access this view in the Developer Tools pane within the AWS Cloud9 editor.

This section provides information about how to access and use **AWS CDK ** in the AWS Cloud9 editor. 

# Working with AWS CDK applications
<a name="aws-cdk-apps"></a>

Use the **AWS CDK Explorer** in the AWS Cloud9 integrated development environment (IDE) to visualize and work with AWS CDK applications.

## Prerequisites
<a name="aws-cdk-apps-prereq"></a>

Install the AWS CDK command line interface. For instructions, see [Getting Started with the AWS CDK](https://docs.aws.amazon.com/cdk/latest/guide/getting_started.html) in the *AWS Cloud Development Kit (AWS CDK) Developer Guide*.

**Important**  
The AWS CDK version that you install must be 1.17.0 or later. You can check which version you're running using **`cdk --version`** command.

## Visualize an AWS CDK application
<a name="aws-cdk-apps-visualize"></a>

Using the AWS Cloud9 IDE AWS CDK Explorer, you can manage the [stacks](https://docs.aws.amazon.com/cdk/latest/guide/stacks.html) and [resources](https://docs.aws.amazon.com/cdk/latest/guide/resources.html) that are stored in the CDK constructs of your apps. The AWS CDK Explorer displays your resources in a tree view using the information that's defined in the `tree.json` file. This file is created when you run the **`cdk synth`** command. By default, the `tree.json` file is located in an app's `cdk.out` directory.

To get started using the Toolkit AWS CDK Explorer, create a CDK application.

1. Complete the first several steps of the [Hello World Tutorial](https://docs.aws.amazon.com/cdk/latest/guide/getting_started.html#hello_world_tutorial) lin the [AWS CDK Developer Guide](https://docs.aws.amazon.com/cdk/v2/guide/getting_started.html).
**Important**  
When you reach the **Deploying the Stack** step, stop and return to this guide.
**Note**  
You can run the commands that are provided in the tutorial, such as **`mkdir`** and **`cdk init`**, on an operating system command line interface or in a **Terminal** window inside the VS Code editor.

1. After you complete the required steps of the CDK tutorial, open the CDK content that you created in the AWS Cloud9 IDE editor.

1. In the AWS navigation pane, expand the **CDK ** heading. Your CDK applications and their associated resources are now displayed in the CDK Explorer tree view. You can also run the following commands in a terminal within AWS Cloud9 to confirm that the CDK feature is working:

   ```
   mkdir mycdkapp
   cd mycdkapp
   cdk init app --language=typescript
   cdk synth
   cdk bootstrap
   ```

### Important notes
<a name="important-notes"></a>
+ When you load CDK apps into the AWS Cloud9 editor, you can load multiple folders at once. Each folder can contain multiple CDK apps, as shown in the preceding image. The AWS CDK Explorer finds apps in the project root directory and its direct subdirectories.
+ When you perform the first several steps of the tutorial, you might notice that the last command that you ran is **`cdk synth`**. This command synthesizes the CloudFormation template by translating your AWS CDK app to CFN. As a by-product, it also generates the `tree.json` file. If you make changes to a CDK app, run the **`cdk synth`** command again to see the changes reflected in the tree view. One example change is adding more resource to the app.

## Perform other operations on an AWS CDK app
<a name="aws-cdk-apps-other-tasks"></a>

You can use the AWS Cloud9 editor to perform other operations on a CDK app in the same way that you use a command line interface. For example, you can update the code files in the editor and deploy the app by using an AWS Cloud9 **Terminal** window.

To try out these types of actions, use the AWS Cloud9 editor to continue the [Hello World Tutorial](https://docs.aws.amazon.com/cdk/latest/guide/getting_started.html#hello_world_tutorial) in the *AWS CDK Developer Guide*. Make sure that you perform the last step, **Destroying the App's Resources**. Otherwise, you might incur unexpected costs to your AWS account.