In this lesson, we’ll explain what makes up the back-end of a web application or website. The back-end can feel very abstract, but it becomes clearer when we explain it in terms of the front-end! To oversimplify a bit, the front-end is the parts of a webpage that a visitor can interact with and see.

Various tools and frameworks can be used to make a webpage, but, at its core, the front-end is composed of JavaScript, CSS, HTML, and other static assets, such as images or videos. Static assets are files that don’t change. When a visitor navigates to a webpage, these assets are sent to their browser.

Visiting a simple website is like ordering delivery from a restaurant: we place an order for our meal, and, once it’s delivered to us, we have it entirely in our possession. In this analogy, we can think of the front-end as everything that’s dropped off with the delivery: the containers, the utensils, and the food itself.

You’ll sometimes hear front-end development referred to as client-side development. Our instinct might be to think of the client as the human visitor or user of a website, but when referring to the client in web development, we’re usually referring to the non-human requester of content. In the case of visiting a website, the client is the browser, but in other circumstances, a client might be another application, a mobile device, or even a “smart” appliance!

While the front-end is the part of the website that makes it to the browser, the back-end consists of all the behind-the-scenes processes and data that make a website function and send resources to clients.