How does a search engine work?

Posted on 6 June 2022

If you want to understand the step-by-step process of how search engines work, and also get your website ranking higher resulting in loads of traffic you’ll need to have a good understanding of the basics. You'll learn how search engines work from a beginner's point of view and you'll be able to understand how they discover your site, make it accessible, and also rank it.

Let's take a deep dive in!

The Search Engine Basics

Before boring you with all the technical stuff let's first understand what a web search engine is, why it is important, and its purpose.

What is a search engine?

Is a software system that is designed to return a list of relevant web pages in response to a search query.

There are three main features of a web search engine:

  • Search engine index. A database of web documents.
  • Search interface. A search engine operating on that database.
  • Search algorithms. (These are a series of programs that determines the relevancy of pages to a given query.

What is the world's largest search engine?

There are popular ones like Google, Bing, Yahoo, Yandex, and Baidu, but Google dominates the industry with over 85% market share.

Statista data for search engine market share
Source Statista

What is the importance of a search engine?

A search engine is a gateway to just about everything we do online. If you are a business, there are some very real and specific benefits to having a consistent, ongoing search engine optimization strategy. For the first time in the history of marketing, users are offering up their actual intent through the words that they type and speak into search engines. So having a good understanding of how web search engines crawl, index, and rank your website will give you leverage above your competitors.

What is the role of a search engine on the internet?

The roles of a search engine on the web can never be understated, discovering both new, old, and updated content on the internet which refers to the term crawling, processing the accessed pages for easy use called rendering, and then storing the information of the pages they've discovered and rendered into a database called index.

its ultimate goal is to make the web search experience better by providing a high-quality, comprehensive, insightful, authoritative, and relevant response to users' information requests.

How does a search engine work step by step?

  • Crawling
  • Processing and Rendering
  • Indexing

All of this is independent of ranking.

Google's step-by-step process

What is Crawling in Search Engine?

Is a process search engines perform to find web pages by following links using (bots) to retrieve information to add to their index. The objective of crawling is to efficiently and quickly gather as many useful and accessible web pages as possible together with the link structure that interconnects them.

What is Rendering?

Is the process of turning hypertext into pixels. The code of a web page that a browser can interact with is turned into a useable aesthetic literally presenting it as a page.

How Google Renders by Martin Splitt

What is SEO Indexing?

Is the act of adding pages and information about them to an index. The search index is a database with well-structured data that the search engine retrieves information and serves to a user that is relevant to their query. if a page is indexed it can be served in response to a searcher query, if a page isn't in a search engine index, it can't rank.

What is ranking in search engines?

Is a site position on the search engine result pages(SERP). The SERP is a list of results that the search engine returns and in theory is relevant to the searcher's query. There are so many ranking factors that determine content relevancy to a given query and for your site to appear at the top of the SERP the quality of the content on your page, the user experience, the quality, and quantity of links pointing to your page and many more will be checked to ascertain if your page merits the position.

Do search engines search the entire web?

Search engines do not search the entire web because there are portions of the web that are referred to as the hidden web and cannot be crawled/discovered, content that falls into this category are:

  • Webmail
  • Online banking
  • Restricted access to social media pages and profiles
  • Some web forums that require registration for viewing content
  • Paywalled services such as video on demand. (Paywalled is a method of restricting access to content with a paid subscription)
  • Pages without links
  • Links to it are marked "rel=nofollow" which is a hint to Google not to follow the path to the end.
  • The page is not in your XML sitemap (yoursite.com/sitemap.xml)

In short, search engines don't crawl all the pages on the web and don't index all the pages they crawl. To check if a page is indexed is to

  • Use the Google search console URL inspection tool.
  • Or paste the page of your website using "site:yoursite.com/page" into Google.

How do search engines crawl?

Search engine bots are constantly crawling the web, for your page to be crawled it must be discovered first. Below is the basic mechanics of how search engines crawl the web.

  • Google accesses a discovered page
  • Add discovered links to the crawl queue
  • Retrieve pre-rendered or HTML content

There are three common ways search engines discover URLs to crawl.

  • XML sitemaps (yoursite.com/sitemap.xml)
  • Hyperlinks from other pages
  • Manual submission via Google search console or Bing webmaster tools

What are bots and crawlers?

Bots also commonly called (crawlers, web crawlers, spiders, spider bots, search engine bots, or search engine spiders) are search engine software that roams the web looking for website content that is discoverable, for it to be rendered and then indexed.

How can I make my new website appear on search engines?

For your new website to rank on the search engines or appear on the search engine results pages(SERP) pages of your new website must be indexed. Indexing is dependent on crawling and rendering. Search engine bots are constantly crawling the web. They start at a known URL and crawl to other pages. Then all being well, they render and index what they find.

What algorithm does Google use for search?

Google uses three algorithms for ranking websites :

  • Google Panda
  • Google Penguin
  • Google Hummingbird

What is an algorithm?

An algorithm is a set of rules that a computer uses to automatically perform a specific task. In the context of SEO, the algorithm is what determines which websites Google ranks highest in search results.

Why are algorithms important?

Algorithms are essential because, without them, the search engine would not know how to rank millions of different websites. Google could just test and rank everything.

But what's the big deal? Why does it matter that Google ranks websites based on algorithms? The big deal is that everyone's results are going to look different on search engines. Some websites are going to rank well, others are going to rank poorly. And there are more than two hundred billion websites out there, which means there are hundreds of billions of different websites. That's the kind of thing that a lot of people would want to see sorted.

Wrapping this up

This article goes over the basics of how search engines work, and understanding the basic mechanics is the first step in ranking your pages in Google's SERP which in turn gives you more visibility and more organic traffic for your website.

Search engines are built with complex algorithms that each of them uses to determine search results. Search engines crawl the web and index every page on their servers. They crawl the web by collecting and analyzing information about web pages, including metadata, keywords, links, and images.

Once a search engine has collected enough information about a web page, they process the information using various algorithms, ranking the web pages based on relevance, freshness, and other factors. Once a page is ranked, it is displayed in search results.

Search engines allow users to search by text, image, video, or a combination of the two. So if your pages are not accessible by the search engine bots to be indexed then the functionality of your site will be hampered.

If you've got questions, please let me know in the comments or reach out to me on twitter

books in a shelf
Allison Kingsley Osadim
I'm a member of the Freelance Coalition for Developing Countries, and a student of the first cohort undergoing Tech SEO consolidation classes with Aleyda Solis international SEO consultant, speaker, and founder of Orainti.

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