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An Introduction to Search Engine Spider: What is it?
A web crawler, also known as a search engine spider, is a Google bot that crawls websites and stores information for the search engine to index.
Consider it this way. When you search for something on Google, those pages and results don’t appear anywhere. They all come from Google’s index, a massive, ever-expanding library of information – text, images, documents and various webpage elements. It’s constantly growing because new web pages are added every day!
The vast majority of pages listed in our results are discovered and added automatically by our web crawlers as they explore the web. This article describes how Search works in the context of your website.
Introducing the three stages of Google Search
Google Search works in three stages, and not all pages take through all three phases:
- Crawling: Google uses a crawler, an automated program that downloads text, images, and videos from web pages.
- Indexing: Google analyzes the page’s text, images, and video files and stores the results in the Google index, which is an extensive database.
- Serving search results: When a user searches on Google, Google returns results that are relevant to the user’s query.
Google crawling
To begin, find out what online pages are available on the internet. Because there is no centralized registry of all web pages, Google must constantly search for new and updated pages to add to its list of available pages. This is known as “URL discovery.” Some pages are well-known because Google has visited them previously. Google discovers new pages when it follows a link from a known page to a new page, such as a hub page linking to a new blog post. Other pages are found when you submit a list of pages for Google to crawl (a sitemap).
When Google discovers the URL of a page, it may visit (or “crawl”) the page to see what’s on it. We use a massive computer network to crawl billions of web pages. Googlebot is the program that performs the retrieval (also known as a robot, bot, or spider). Googlebot uses an algorithm to determine which sites to crawl, how frequently to crawl them, and how many pages to retrieve from each site. Google’s crawlers are also programmed to try not to crawl the site too quickly to avoid overloading it. This mechanism is based on site responses (for example, HTTP 500 errors mean “slow down”) and Search Console settings.
Googlebot, on the other hand, does not crawl all of the pages it discovers. Crawling may be blocked on some pages by the site owner, inaccessible without logging in, and duplicates of previously crawled pages. Many sites, for example, are accessible via the www (www.example.com) and non-www (example.com) versions of the domain name, even though the content is identical in both cases.
During the crawl, Google uses a recent version of Chrome to render the page and run any JavaScript it finds, similar to how your browser renders pages you visit. Rendering is important because many websites use JavaScript to bring content to the page. Without rendering, Google may miss that content.
Crawling is dependent on Google’s crawlers being able to access the site.
How Frequently Google Crawls Your Website?
Web crawling is an ongoing process. The software crawls previously indexed pages to replace dead links and page redirects. However, they follow a set of rules that give them more leeway in deciding which pages to crawl.
Crawling policies specify how frequently and how to crawl pages.
Googlebot crawls your site regularly based on algorithmic crawl budgets associated with your PageRank.
Google developed the PageRank scale to assign a score to each page based on many factors. Page importance, content quality, the number of links, and individual page authority are among these factors.
The more time Googlebot crawls your site, the higher your PageRank score.
The crawl can be conducted every few hours for pages with higher authority or those that refresh frequently. However, other pages with no substance can take months or years.
Looking at Google Search Console and isolating the individual page will show you when Google last crawled that particular page on your website.
Google Indexing
Google attempts to understand what a page is about after crawling it. Indexing is the process of processing and analyzing textual content as well as key content tags and attributes such as title elements and alt attributes, images, videos, and more.
During the indexing process, Google determines whether a page is a duplicate or canonical of another page on the internet. The canonical page is the one that appears in search results. We first group internet pages of similar content to determine the canonical. Then we select the one that is most representative of the group. Alternate versions of the pages in the cluster are helpful in different contexts, such as looking for a specific page or searching on a mobile device.
Google also collects signals about the canonical page and its contents, which may be used in the subsequent stage when the page is served in search results. Some indications include the page’s language, the country where the content is localized, the page’s usability, and other factors.
Google index, a massive database hosted on thousands of computers, could store the data about the canonical page and its cluster. Indexing is not guaranteed; not every page processed by Google is indexed.
Indexing is also affected by the page’s content and metadata.
How Google’s spider crawls and indexes, your site may be influenced by factors such as the domain name, backlinks, and internal links.
SEO experts recommend only allowing essential parts of your website to be indexed to achieve accurate search engine rankings. Tags, categories, and other non-essential pages do not need to be indexed, and it may benefit your website’s rankings if they are not.
You can check how Google is indexing your site and identify what can be done to improve its performance using Google’s Search Console, also known as Google Webmaster Tools. The more you add, change, and improve your content, the more activity Google spider detects.