In this part our focus shifts towards the backend, that is, towards implementing functionality on the server side of the stack. We will implement a simple REST API in Node.js by using the Express library, and the application's data will be stored in a MongoDB database. At the end of this part, we will deploy our application to the internet.

a. Node.js and Express
b. Deploying app to internet
c. Saving data to MongoDB
d. Validation and ESLint