You started by evaluating the HTTP core module in Node.js and saw how it processes requests. It receives and sends both headers and data back to the calling client.
You learned the benefits of using a web framework like Express. You gained some knowledge on its features and important concepts.
Express handles numerous things like route management, and how to construct different types of responses to handle the upload and download of files. Additionally, Express handles the lifecycle of a request to perform tasks, such as logging or acting on authentication credentials.
You became familiar with most of the concepts in a series of exercises. You should feel fairly confident about how to create a RESTful API by using Express and Node.js. As part of learning to construct APIs, you looked at different ways of interacting with your API. You found that you could use a browser, code, or a client like cURL to send requests.
At this point, you should have a good foundation to build web applications with Express. You also understand that there's more to learn about how to create and work with APIs, especially in securing your API.