The following are the prerequisites for this recipe:

• A working AWS account
• A configured AWS CLI, as discussed in the Your first Lambda with the AWS CLI recipe of Chapter 1, Getting Started with Serverless Computing on AWS
• You have followed the steps in the recipe Your first API using the AWS CLI from Chapter 2, Building Serverless REST APIs with API Gateway, and created and deployed an API with a GET URL of the form https://<rest-api-id>.execute-api.us-east-1.amazonaws.com/dev/greeting/Heartin
• You are familiar with CodePen or any browser-based tool from which we can send JavaScript requests to our API