Learning the backend

So far, we have only been dealing with the frontend. The frontend is the part that is running on the client side, which could be any device that the user is using, such as a phone, laptop, or tablet. In order for websites to do interesting stuff, we also need a backend. For example, if you want to log on to a website, this website somehow needs to know whether this user exists.

This is the job of the server-side code, the backend. This is code that is running not on the device of the user, but on some sort of server elsewhere, which is often owned or leased by the company hosting the website. Hosting the website usually means that they make it available to the world wide web by placing it on a server that can take outside requests via a URL.

The code on the server does many things, all related to deeper logic and data. For example, an e-commerce store has a bunch of items in the shop that come from a database. The server gets the items from the database...