How websites work

To understand technical SEO, it's helpful to know how a website works. Knowing how a website works will help you understand issues that a search engine might run into when trying to understand your website and ways that you can help search engines process your website more effectively and efficiently.

What is a Website?

A website is really just a way to publically collect and display information. It's made up of pages of code. This code describes the structure, content, appearance, and action of a website. There are three primary types of code: HTML, CSS, and JavaScript.

HTML — The structure and content of a page (titles, body content, etc.)

CSS — The appearance of a page (color, fonts, etc.)

JavaScript — How a page moves or reacts to a specific input (interactive, dynamic, etc.)

How Does a Website Get on the Internet?

Each page is named with a URL (Uniform Resource Locator) and each URL is attached to a domain. Website domains don't exist in space — they must first be set up and given a home.

First, you need to give your website a domain name and register it with a registrar like GoDaddy or HostGator. These are just companies that manage the reservations of domain names. Then, your domain name must be linked with an IP address and stored on a domain name server (DNS). A DNS does two things:

  1. A DNS translates domain names — for example, — into IP addresses (Internet Protocol addresses) — for example, 226.204. In other words, we need a DNS service to translate human-readable words into machine-readable numbers.
  2. A DNS hosts the IP address. This line of numbers must be stored on a massive computer called a server. DNS providers are companies that have a bunch of servers for storing this information that will send that information to your computer via the World Wide Web (ie the internet).

Note: It's important to know the difference between a domain and a hosting service. You can buy a domain, but it doesn't really exist anywhere until you pay to have it hosted on a server.

How Users Interact with Websites 

When you access a website, your computer is using a browser — think Safari, Firefox, or Chrome. When you know the exact web address (URL) for a web page you can type it into your browser or you can click a link to that URL.

When a user requests a domain using a browser, a series of events take place.

  1. The browser will request the domain from the server.
  2. The browser will render — or decode — the HTML, CSS, and JavaScript that a developer has written out.
  3. The browser will then display that information to you in the form of a familiar webpage with recognizable elements like a title, paragraph, and hyperlinks.

Note: Javascript can slow the time it takes for your browser to load a webpage because it takes longer to render than HTML and CSS.

When you don't know the exact address of a website, or you don't know which website you want to go to for information, you'll use a search engine by typing in a question or term related to whatever website or information you are looking for.

How search engines interact with websites

Search engines are designed to help humans find information on the web. One helpful analogy, introduced by Google Developer Advocate Martin Splitt, is to compare search engines to librarians and the internet to one massive library (or library catalog). A librarian must go through a collection of books, consider the content of the books, and then decide how those books relate to other books and how they should be labeled.

Similarly, search engines have to go through the vast collection of information on the internet and parse the code to organize it for users. They go through and parse this information by crawling and rendering it with search engine crawlers. Once the search engine has crawled and rendered a page, it can index it into its database. Once the page is in the index (or catalog), the search engine can match the content of a web page with a question (or terms) that a user types in.

Technical SEO Journey Infographic