Serverless technologies like AWS Lambda allow us to build our applications out of small, independent functions that can be called based on events such as an API call. By default, it's not possible to call an AWS Lambda function from the Internet - it's safely stored within AWS cloud, following the principle of least privilege. In order to create a REST API to call an AWS Lambda function we need to use API Gateway. Luckily, with AWS CDK, we can create a LambdaRestApi in 3 lines of code and this is exactly what we're going to learn in this quick lesson!