AWS CDK

What it is

AWS CDK (Cloud Development Kit) is an infrastructure as code framework that allows defining AWS resources using real programming languages instead of YAML/JSON. Code is synthesized to CloudFormation for deployment.

CDK vs Terraform vs CloudFormation

Aspect	CDK	Terraform	CloudFormation
Language	TypeScript, Python, etc.	HCL	YAML/JSON
Abstraction	High-level constructs	Resources	Resources
Multi-cloud	No	Yes	No
State	CloudFormation	Terraform state	CloudFormation

Key concepts

Concept	Function	Example
App	Entry point, contains stacks	`new cdk.App()`
Stack	Deployment unit (= CloudFormation stack)	`MyServiceStack`
Construct L1	1:1 mapping with CloudFormation	`CfnBucket` (low level)
Construct L2	Abstractions with sensible defaults	`s3.Bucket` (auto permissions, encryption)
Construct L3	Complete patterns	`LambdaRestApi` (API + Lambda + permissions)

TypeScript example

const fn = new lambda.Function(this, 'Handler', {
  runtime: lambda.Runtime.NODEJS_20_X,
  handler: 'index.handler',
  code: lambda.Code.fromAsset('lambda'),
});
 
const api = new apigateway.RestApi(this, 'Api');
api.root.addMethod('GET', new apigateway.LambdaIntegration(fn));

Why it matters

CDK allows defining infrastructure with real programming languages, enabling abstractions, unit testing, and pattern reuse that are not possible with HCL or YAML. For development teams that already master TypeScript or Python, it lowers the barrier to entry for IaC.

References

CDK Documentation — Official documentation.
CDK Patterns — Architecture patterns.
CDK Best Practices — AWS, 2024. Official best practices.