Search engines serve as your online gateway. They analyze large amounts of information on a website and decide how effectively it answers a given inquiry. 

But, with so much information to sort through, how do search engines actually work?

Your material must first be made available to search engines in order to appear in search results. It is perhaps the most crucial aspect of SEO: If your site cannot be found and read, you will never appear in the SERPs.

If you are a developer, a web designer, a designer, a business owner, a marketing or sales professional, any sort of website owner, or are simply considering developing a personal blog or website for your company, you will need to understand how search engines work in order to stay ahead. 

You will also need to know how search engines work in order to stay ahead of inevitable search engine algorithm changes, so unfortunately, this is the knowledge that you will need to keep developing in the longer term.

Understanding how search works will help you develop a website that search engines can easily and clearly understand, which has a variety of additional benefits. 

This is the first step you must do before beginning any Search Engine Optimization or Search Engine Marketing projects.

Search engines use complex algorithms to determine the quality and relevance of every page in order to discover, categorize, and rank the billions of websites that comprise the internet. 

It is a complicated process requiring a large quantity of data, all of which must be presented in an easy-to-understand format for end users so they can actually use the resulting search results.

Search engines analyze all of this data by examining a variety of ranking variables depending on a user’s query. This includes relevance to the inquiry a user typed in, content quality, site performance, metadata, and other factors. 

Each data piece is integrated into the complex algorithms that make search engines work, all to assist search engines in determining the overall quality of a page. The website is then rated and given to the user in their search results depending on the search engines’ calculations.

Let’s take a look at the basics of how search engines work. We will cover search engine algorithms for Google and other search engines, as well as mysterious-sounding terms like search engine crawlers, search engine spiders, search engine bots, and the all-important concepts of crawling, indexing, and ranking. 

So, if you have ever been curious about understanding how search engines actually work, read on below for the answers!

How Does a Search Engine Work?

Search engines are sophisticated computer programs. They must perform extensive preparatory work before allowing you to input a query and search the web so that when you click “Search,” you are provided with a collection of precise and high-quality results that answer your question or query.

This preparation effort is separated into three major parts. The first step is the process of discovering information, the second stage is organizing all of that information, and the third stage is ranking it in order of how useful they think it is.

In the world of SEO, this is referred to as crawling, indexing, and ranking. It is how Google works, and it is how the vast majority of other search engines work, too. 

Crawling and indexing are pretty straightforward when you understand them, but ranking is a much more complex process. We will break down those three steps in more detail below, but there is another factor to consider first: the algorithm.

During this process, decisions are taken to assess the value that any website might have to offer to the end user. An algorithm controls these judgments. Understanding how an algorithm works aids in the creation of content that ranks higher on each site.

These algorithms include RankBrain for Google and YouTube, Space Partition Tree And Graph (SPTAG) powering Bing, and DuckDuckGo’s proprietary codebase. 

Each platform employs its own set of ranking factors and localized versions of its algorithms to decide where webpages appear in search results.

Because search engines make use of their own proprietary search algorithms, appearing at the top of the search engine results page (SERP) for one search engine does not always guarantee you will appear at the top of the search engine result page for other search engines.

Some prioritize written content quality, while others prioritize user experience and link building. Understanding what the search engine wants is essential for ranking well in the SERPs. We will look at this in more detail later.

What is Search Engine Crawling?

Crawling is the process by which search engine web crawlers (also known as bots or spiders) explore and download a page in order to locate other sites based on the links hosted on that web page. Crawling (and indexing) are the foundations of how any search engine works.

Pages that are already known to the search engine are crawled on a regular basis to see whether there have been any changes to the page’s content since the previous time it was crawled. 

If a search engine finds changes to a page after crawling it, it will update its index to reflect the changes.

To identify and access online sites, search engines employ their own web crawlers.

All commercial search engine crawlers start crawling a website by downloading the robots.txt file found on the site, which provides rules governing which pages search engines should and should not crawl on the domain. 

The robots.txt file can additionally include sitemap information, which is a list of URLs that the site wishes a search engine crawler to explore.

To determine how frequently a website should be scanned and how many pages on a site should be indexed, search engine crawlers employ a variety of algorithms and criteria. A page that changes regularly, for example, may be crawled more often than one that is not modified very often.

Search engines will generally try to crawl and index every URL they come across. If the discovered URLs refer to a non-text file format, such as an image, video, or audio file, search engines will often be unable to access the file’s content other than the accompanying filename and metadata.

Despite the fact that a search engine can only extract a limited amount of information from non-text file formats, they are still able to be indexed, ranked in search results, and get traffic.

Crawlers uncover new pages by re-crawling previously visited pages and then extracting links to other pages to find new URLs. These newly discovered URLs are added to the crawl queue and will be downloaded later.

Crawling search engines may locate any publicly available webpage on the internet that is connected from at least one other page by following links. This is the main purpose of the crawling process.

Sitemaps can also be crawled by search engines to locate new pages. Sitemaps are collections of URLs that may be generated by a website to provide search engines with a list of pages to crawl. 

These can assist search engines in discovering material that is hidden deep inside a website. This is why it is worth having an XML sitemap for your web content. 

It will reduce crawl errors and make it as easy as possible for your important pages to get indexed on the search engines as fast as possible.

Essentially, crawlers are computer program bots that move from one website to other websites along links, like a spider crawling along a thread of its web. 

It starts with already indexed pages and then moves to external websites, adding any new page it finds to its huge database of web pages. Search engines send these bots out constantly in order to keep Google search results (and other results in the search engine market) from becoming outdated.

What is a Crawl Budget?

Crawl budget is a product of crawl rate and crawl demand. It is, essentially, the number of URLs on a website that any given search engine will crawl in a particular time period. There is a limit to how many sites web crawlers can explore at a time.

Crawl budget is limited to ensure that a website’s server is not overburdened with too many simultaneous connections or too much pressure on limited server resources, which might negatively affect the user experience of visitors to the site.

Every IP has a limit on the number of connections it can manage, and crawling and indexing take up some of those connections. 

A shared server can host several websites, and therefore, if a website shares a server or IP address with multiple other websites, it may have a lesser crawl budget than a website located on a dedicated server.

On the other hand, a website housed on a cluster of dedicated servers that respond rapidly will often have a bigger crawl budget than a website hosted on a single server that answers slowly when there is a lot of traffic. 

Quick response enables web crawlers to do their jobs more efficiently. That is just an unavoidable part of how search engines work: page speed matters.

It is crucial to remember that just because a website answers quickly and has the resources to support a high crawl rate does not guarantee search engines will want to devote a large amount of their own resources to it if the material is not deemed significant enough. 

Your content has to be good enough for them to want to spend their limited budget on crawling and indexing your pages.

What is Search Engine Indexing?

After a search engine has completed its crawl of a page, the next step that it moves on to is called indexing. 

Let’s dive into the nuts and bolts of the indexing process that search engines employ to store information about web sites so that they can provide relevant, high-quality results almost instantaneously. 

Once the web crawlers have found the information that the search engine needs, that info needs to be filed in an accessible way so that it can be used to make the search engines work properly.

Indexing is the technique by which a search engine works to arrange information prior to a search in order to provide lightning-fast results to queries. 

Search engines would operate very slowly if they had to crawl individual pages for keywords and subjects in order to find relevant material. Search engines instead employ an inverted index, often known as a reverse index.

An inverted index is a system that compiles a database of text elements as well as references to the documents that contain those components. 

Then, using a technique known as tokenization, search engines condense words to their basic meaning, lowering the scale of resources required to store and retrieve that data. 

This method is far more efficient than listing all known web pages and comparing them against all possible keywords and characters that users could search for.

Search engines may keep a highly compressed text-only version of a document containing all HTML and metadata in addition to indexing pages. This cached document is the most recent snapshot of the page seen by the search engine.

In Google, you may access the cached version of a page by clicking the small green arrow next to each search result’s URL and selecting the cached option. You may also use the ‘cache:’ Google search operator to see the cached version of the page in question. 

The Google index is one of the most effective ways that a user query can find an older or defunct web page.

Bing provides the same option to see the cached version of a page by clicking a green down arrow next to each search result, but it does not yet support the ‘cache:’ search operator.

How do Search Engine Rankings Work?

When a user performs a search and inputs a query, the third and last stage is for search engines to pick which sites to show in the SERPS and in what order. 

There are many ranking factors, and each search algorithm prioritizes them differently, but the most important to understand is the Google search algorithm.

This is accomplished by employing search engine ranking algorithms. In their most basic form, these algorithms are pieces of software with a set of rules that assess what the user is looking for and determine what information to deliver as a result of the query. 

They aim to provide relevant results to each user query, which is a complex process. These rules and choices that the search engine algorithm uses to identify relevant results are based on the information included in the search engine’s index.

Search engine ranking algorithms have changed and become quite intimidatingly complicated over time. 

It used to be that matching the user’s query with the title of the page was pretty much all the algorithm did, but that is no longer the case. 

Any modern search engine algorithm will use a huge number of ranking factors to find and display relevant results, and all search engines work slightly differently from each other.

Before making a conclusion, Google’s ranking system considers many factors: more than 255 criteria, the details of which are unknown to everyone outside the Google team.

Things have changed dramatically, and now machine learning and computer programs are in charge of making judgments based on a variety of characteristics that extend beyond the content of a web page.

How do Search Engine Algorithms Work?

The first stage of how search engine algorithms work is for the search engines to determine what type of information the user is actually searching for. To do so, they break down the user’s query (specifically the search phrases) into a number of useful keywords.

A keyword is a term with a defined meaning and function. Machine learning has enabled search engine algorithms to connect relevant terms together, allowing them to deduce a portion of your purpose from the word you use. 

For example, if you include the word “buy” in your query, they will limit the results to shopping websites.

They are also capable of interpreting spelling errors, comprehending plurals, and extracting the intended meaning of a query from natural language, including spoken language for Voice Search users.

The second step in how the algorithms for search engines work is to search their index for sites that can provide the best response to a particular query. 

This is a critical stage in the process for both the search engines themselves and the website owners whose content may be returned in the search engine results pages.

Search engines must produce the best possible results in the shortest amount of time in order to keep their users satisfied, while website owners want their websites to be picked up in order to receive traffic and views.

This is also the point at which making use of effective search engine optimisation strategies could have an effect on the algorithms’ decisions. You can take advantage of how search engines work to push your content further up the search results.

To receive visitors from search engines, your website must be toward the top of the first page of results. It has been well established that the majority of users (both on desktop and mobile) click on one of the top five results. Appearing on the second or third page of search results will attract almost no visitors to your page.

Traffic is only one of the benefits of SEO; if you reach the top rankings for keywords that are relevant to your organization, the other benefits are numerous. 

Understanding how search engines function can help you improve your website’s ranks and traffic. The next part of the rankings system is PageRank.

What is PageRank?

“PageRank” is a Google algorithm named after Larry Page, one of Google’s founders. Yes, that is right, it is not referring to web pages! 

It is a value assigned to each page that is determined by counting the number of links referring to that page in order to assess the page’s value in relation to all other pages on the internet. 

Each individual link’s worth is determined by the number and value of links that lead to the page with the link.

PageRank is merely one of several signals considered by Google’s massive ranking system. Google initially supplied an estimate of the PageRank values, but they are no longer publicly viewable.

While PageRank is specifically the name for the Google version of this system, a comparable link equity metric is calculated and used by all major search engines. 

Some SEO tools attempt to estimate PageRank based on their own logic and calculations, but this is not necessarily a reliable measure.

Pages use links to convey PageRank (otherwise known as link juice or link equity) to other pages. When a page links to material on another page, it is interpreted by the search engines as being a vote of confidence and trust. 

The number and quality of these links influence the linked-to page’s relative PageRank.

PageRank is distributed evenly among all detected links on the page. For example, if your website has five links going out of it, each link passes 20% of the page’s PageRank to the target pages. PageRank is not passed by links with the rel=”nofollow” tag.

How to Help Search Engines Crawl Your Site

It is important for site owners to know how Google is engaging with their content. Google Search Console is the best way to do this, as it can tell you quite a lot about how each blog post or page on your site is performing in the search engine rankings for relevant queries. 

The metrics are put on display through easy-to-read visualizations like the knowledge graph, making it as easy as possible to see how the ranking factors are affecting your traffic.

If you have used Google Search Console and discovered that some of your important pages are missing from the index or that some of your unimportant pages have been incorrectly indexed, there are some optimizations you can use to better tell Googlebot how you want your content crawled. 

It is possible to instruct search engines how to engage with your content in detail, and telling search engines how to crawl your site might offer you more control over what is indexed.

Most people think about ensuring that Googlebot can reach their critical pages, but it is easy to overlook the fact that there are undoubtedly pages you do not want Googlebot to find. 

These might contain ancient URLs with minimal content, duplicate URLs (such as e-commerce sort-and-filter parameters), special promo code sites, incomplete pages, and various other things that might make you look unprofessional to Google.

Use robots.txt to guide Googlebot away from specific pages and portions of your website.

Robots.txt files are situated in the root directory of websites and use particular robots.txt directives to advise which portions of your site search engines should and should not scan, as well as the pace at which they crawl your site.

Not all web robots adhere to robots.txt. Scammers and data harvesters create bots that do not adhere to this standard. In fact, some unscrupulous actors utilize robots.txt files to determine where you have stored your confidential information. 

Although it may appear rational to restrict crawlers from private pages such as login and administrative pages so that they do not appear in the index, putting the address of those URLs in a publicly available robots.txt file also, unfortunately, means that persons with malicious intent may reach them more easily.

How do Personalized Results in Search Engines Work?

When you search for information, the results that you receive will be quite similar to the results that other people get when they use the same search query. However, depending on your online behavior, some pages may be prioritized over others when you search.

Google will tailor the SERP results to some extent. The user’s location is the most evident part of this customization. 

Search engines will customize their results to include possibilities that are geographically closer to the user if a user searches for a specific service or product. 

This is critical for businesses such as restaurants, where customers may not want to see alternatives that are miles away from them.

When a user searches in a language other than English, search engines prefer results in that language because they are more relevant to the user. Furthermore, search engines will emphasize translated versions of websites that are already available in many languages.

In order to deliver more tailored results, search engines will also examine a user’s search history and behavior. 

If a person searches regularly for news-related content, for example, search engine results may highlight news sites. 

Similarly, if a user has already visited a specific website, search engines follow their history and are more likely to provide that page as a suggestion in the future. They will also often track this, telling you when you last visited a web page.


Search engines have evolved into extremely complicated computer programs with a number of algorithms and bots incorporated into their workings. Their user interface may be basic, but the way they function and make judgments is anything but.

Crawling and indexing are the first steps in the process of how search engines work. During this phase, search engine crawler bots collect as much information as possible for all publicly accessible websites on the internet.

Search engines work to find, analyze, sort, and store this information in a way that search engine algorithms can utilize to make a judgment and offer the best results to the user to match their search queries.

They have a massive quantity of data to handle, and the process of search engine crawling, indexing, and ranking is totally automated by search engine bots. 

Human interaction is only needed in the process of developing the rules that will be employed by the various types of search engine algorithm, although even this stage is being increasingly replaced by computers using artificial intelligence.

Your role as a webmaster is to make crawling and indexing easy for them by designing websites with a clear and straightforward layout so that when search engines discover your site, they can understand it easily and grasp the content of all the pages on your website.

Once they can “read” your website without any problems, you must ensure that you provide them with the correct signals to assist their search ranking algorithms in selecting your website when a user types a relevant query.