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How does Google Search Works: Crawling, Indexing, Ranking and Serving

Last Updated : 01 Dec, 2023
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Google is the most used search engine in the world. It contains billions of pages in different categories. Also, new pages are added continuously. Google discovers, crawls, and serves web pages through a complex and automated process that involves several steps. Well, it happens through four main processes: crawling, indexing, ranking, and serving.

What is Crawling in SEO?

Google crawlers are programs that Google uses to scan the web and find new or updated pages to add to its index. Google crawlers check all kind of content including text, images, videos, webpages, links etc. Google crawlers follow links from one page to another and obey the rules specified in robots.txt files.

In order to develop and maintain the search engine’s index, web crawling aims to thoroughly and methodically scour the internet for fresh content. Search engines can keep their search results current and relevant to users queries by regularly discovering and reviewing web pages.

How does crawling works?

Crawling is a process to discover and update new pages on google index. Well known crawler of Google is known as Google Bot. It is responsible for fetching web, moving from one page to another through links and adding pages to Google’s list of known pages. Google crawls pages deposited by website owners on search console or through there sitemaps. Sitemap is a file that tell how many pages are in website and its structure. Google also crawls and index pages automatically depending on several factors

Factors that determine which pages to crawl

  • The popularity and authority of the site and page, measured by the number and quality of links from other sites and pages.
  • The freshness and frequency of updates on the site and page, measured by the date and time of the last modification or publication.
  • The crawl budget and rate limit of the site, which are determined by the size, speed, and responsiveness of the site.
  • The crawl demand and priority of the page, which are determined by the user interest, query freshness, and page importance.
  • The crawl rules and directives of the site, which are specified by the site owner in robots.txt files, sitemaps, meta tags, HTTP headers, and other tools.

So, after crawling your site is known to google or discovered by google.

How does Google crawler see pages?

Google crawlers looks the page from top to bottom. However google bot does not sees pages exactly as humans do because it does not render them with CSS or execute JavaScript. Google bot looks and analysis the content of the page and tries to decide the purpose of page. Google bots looks at other signals the page is providing such as robot.txt file which tells googlebot which page is allowed to crawl.

You can prevent pages from Googlebot crawling using robot.txt file

  • pages with duplicate content
  • private pages
  • URLs with query parameters
  • pages with thin content
  • test pages

Let us see how google bot works:

  • The first thing googlebot sees in page is <!DOCTYPE> declaration which tells google bot about version of HTML
  • Next it will see the html tag in the page it might also have language attribute. This helps Googlebot to understand the content and provide relevant results
  • After that googlebot will look at head tag which contains title which is not shown to users and then meta description tag which defines short summary of the page that may appear in the search results.
  • The <head> tag may also contain links to external resources, such as stylesheets, scripts, icons, and fonts, that affect how the page looks and behaves
  • The <body> tag may have various elements that structure and format the content, such as headings (<h1>, <h2>, etc.), paragraphs (<p>), lists (<ul>, <ol>, etc.), tables (<table>), images (<img>), links (<a>), forms (<form>), and more.

For example:

Googlebot may use headings to identify the main topics of the page, images to enhance the visual appeal of the page, and links to discover new pages to crawl. After that it will check the closing head tag

What influences the crawler’s behavior?

Following are the factors which affects crawler’s behavior

  • It has a crawl budget, means the number of pages that it will crawl is limited in a specific time period if the crawl limit of day of your site is over than crawlers wont crawl more pages
  • Crawl demand represents interest of google in a particular website.
  • There are various algorithms which guide the crawlers which links to follow, prioritizing pages on basis of relevance and freshness, no indexing duplicate pages.
  • It respects directives and meta tags on webpages that indicate how certain content or pages should be handled, like noindex, nofollow, or nosnippet.

What is Indexing in SEO?

Big collection or massive library of Webpages, used by google to provide results to there users. It is process of analyzing the webpages on different factors and storing them to index. Google Index is a massive database of google used for storing web pages and organizing them in proper manner. So that google retrieve information and provide them to users when they search on google.

The index is the foundation for generating search engine results pages (SERPs). It allows search engines to quickly match user queries with relevant web pages and display them in a ranked order. Regularly updating the index and refining ranking algorithms are ongoing processes that ensure search engines provide the best possible results for users.

Indexing: How Google Organizes Web Pages

Google will index your site based on several factors-

  • Page titles: The title of a web page is usually displayed in the browser tab and in the search results. It should describe the main topic or purpose of the page in a concise and accurate way.
  • Headings: Heading are important part of webpage. It should contain important and relevant keywords. Single H1 tags should be used page.
  • Meta descriptions: Meta description are small block of text which tells users about the content of the website. They describe your whole website to users. It is shown below your website title shown on google. So don’t make it too short or too long and add why people should visit your site in it.
  • Keywords: Keywords are words or phrases that describe what the web page is about. They should match with the users searches on google and you website should not look AI like.
  • Images: Images can enhance the visual appeal and understanding of a web page. They should have descriptive alt text (alternative text) that explains what they show in case they cannot be displayed or accessed by screen readers.
  • Site structure: It refers to the way your site is organized and how different pages are linked together. How easy navigation you are providing to users? Users should not struggle to find the content of there need.
  • Mobile-friendliness: Website should be mobile friendly because google knows they have to serve site in front of users of different platforms. A mobile-friendly web page should load fast, use responsive design, avoid pop-ups, and provide a user-friendly interface.
  • Loading speed: Loading speed is the how fast your webpage loads its content such as text, images, scripts etc. Factors that affect loading speed include server response time, image sizes consider using webp for better loading, cache, code efficiency etc.

What is Ranking in SEO?

Ranking is the process by which search engines determine the order in which web pages appear in search engine results pages (SERPs) in response to a user’s search query. It is a critical step in the search engine process as it directly affects the visibility and accessibility of web pages to users.

The ranking process is a continuous cycle, with search engines striving to deliver the most relevant and high-quality results to users. It is a complex and dynamic field, as the internet’s content and user behavior are constantly evolving, requiring search engines to adapt their algorithms and ranking factors accordingly.

Ranking: How are URLs ranked by search engines?

Search engines rank URLs using a complicated method that includes a number of algorithms and criteria. The objective is to rank web pages in search engine results pages (SERPs) according to the quality and relevancy of their user-response content. Here is a summary of how search engines rank URLs:

  • Crawling and Indexing: Search engines must first find and index URLs before ranking them. Web crawlers visit websites, gather information, and then store it in a structured database (the search engine’s index) in order to accomplish this.
  • Query Analysis: When a user enters a search query, search engines analyze the query’s keywords, phrases, and context to understand the user’s intent.
  • Keyword Matching: Search engines look through their database for web sites with information pertinent to the user’s query. This entails comparing the keywords in the query to the keywords present in the page’s metadata and content.
  • Relevance Assessment: Each web page’s relevancy to the user’s query is evaluated by search engines. They take into account a number of things, such as:
    • Keyword Relevance: How well the page’s content matches the query keywords.
    • Content Quality: The overall quality, depth, and relevance of the content on the page.
    • Backlinks: The quantity and quality of backlinks pointing to the page, indicating trust and authority.
    • User Engagement: Metrics like click-through rate (CTR), time spent on the page, and bounce rate.
    • User Intent: How well the page fulfills the specific intent behind the user’s query.
  • Scoring and Ranking: Each web page receives a score from search engines based on their evaluation of its quality and relevancy. The page’s ranking in the SERP is based on this score. Higher-scoring pages are ranked higher and show up first in the search results, whereas lower-scoring pages show up further down the page or even don’t show up at all.
  • Algorithm Factors: Numerous ranking variables are used by search engines, including on-page elements like content, keyword usage, and metadata, off-page factors like backlinks and social signals, and user experience factors like click-through rate, dwell duration, and mobile friendliness. Search engines might differ in the specifics of their algorithms and the weights assigned to certain factors.
  • Freshness and Recency: The freshness of the material is an important ranking factor for several types of queries. Particularly for concerns pertaining to news or current events, timely and current information may be preferred.
  • User Localization: To deliver localized results, search engines take the user’s location into account. For inquiries about companies, services, and locations, this is essential.
  • Personalization: Based on the user’s search history and preferences, search engines may tailor the results. The goal of personalization is to deliver outcomes that are customized to each user’s preferences and requirements.
  • Feedback and Iteration: Users interactions with search results are continuously monitored by search engines. They use this information to improve search engine results, hone ranking algorithms, and thwart spam or low-quality content.
  • Algorithm Updates: In order to enhance the quality of the results, address new trends, and combat manipulation, search engines routinely alter their ranking algorithms. These modifications could include adding new variables, altering the weights of current variables, or changing the ranking criteria.

The ranking process is quite dynamic and is influenced by the constantly changing digital environment. As a result, in order to ensure that their URLs appear high in search engine results, webmasters and content producers need to stay up to date on SEO best practices.

Serving: How Google Shows Web Pages

Serving is the process of returning relevant results for a user’s search query from the index. When someone searches for something on Google, Google matches the query against its vast index and provides the most relevant results based on hundreds of ranking signals such as more views, quality of article, interaction time with user etc.

Several Steps of Google Serving are following

1. Parsing:

Its a process of breaking down the users search query into small keywords to make it easier to understand


Someone searched ” How to make a website” Google will understand this as set of keywords like “How to”, “make” , “website”. In this way it it understand that user is searching the process to make website

2. Matching:

After understanding google will search the webpages in its index which have the keywords and phrases similar to it.


If someone searches for “how to make a website”, Google will match the query with the pages that have the words “how to”, “make”, and “website” in their content or metadata.

3. Ranking:

Its a process of giving order to webpages which are found from Google index of that search query.


When you search something on google it provides a lots of webpage titles as result.

The quality and the relevancy of the site will decide its order in google results. It ranks the pages that have the most relevant and high-quality content on making a website higher than the pages that have less relevant or low-quality content.

4. Displaying:

Displaying is the process of showing the ranked results to the user in a user-friendly and informative way.

For example:

If someone searches for “how to make a website”, Google will display the results with titles, snippets, images, ratings, and other features that help the user decide which result to click on.

Frequently Asked Questions (FAQs)

Can Google crawl and index password-protected web pages?

No, Google can’t access content behind login walls or password protection.

What is the PageRank algorithm, and how does it affect crawling?

PageRank ranks web pages by importance, influencing crawl frequency and indexing.

Does Google prioritize mobile-friendly web pages during crawling?

Yes, Google prioritizes mobile-friendly pages for its mobile search index.

How does Google handle JavaScript-based content during crawling?

Google can crawl and index JavaScript-rendered content but prefers static HTML.

Can Google crawl and index content within iframes?

Yes, Google can index content within iframes if accessible through HTML.

What happens when Google encounters a “nofollow” attribute on a link?

Google won’t follow or pass PageRank through “nofollow” links.

How often does Google recrawl web pages to update its index?

It depends on the page’s importance and update frequency, ranging from days to months.

What role does the Googlebot play in the crawling process?

Googlebot is Google’s web crawler that fetches and indexes web pages.

How does Google handle duplicate content across different web pages?

Google identifies and may consolidate duplicate content under one canonical URL.


Google’s search engine is continually evolving, and it uses sophisticated algorithms to provide the most relevant and high-quality search results to users. Website owners and SEO professionals often work to optimize their websites for better visibility in Google’s search results.

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