What Is A Crawler And How Does It Works?

Are you a SEO professional? We have come up with this knowledge rich post which will help you to understand the working of search engine and get exciting search rank results.

Do you know the whole SEO process starts with a crawler, which refers to a bot or software program used by search engines to systematically browse and index web pages on network.

What is a crawler?

A crawler also known as spider is responsible for discovering new pages, updating existing pages and collection information about the content and structure of a website. The crawler visit some known web pages and discover the internal links present on that page. This whole process is known as Web Crawling.


The primary role of a crawler is to visit and analyze the content and meta data of the webpage so that it can understand the topics, keywords and quality. This information is used by Google search engine for indexing and determining its ranking in SERPs. The more your website is accessible and effectively optimized for a crawler/spider, the higher are the chances of its pages being indexed and ranked well.


Here are the steps and working of a web crawler that we as the top digital marketing agency in US observe and follow.

Working of a Web Crawler

Start with a Seed URL: The task begin with a set of initial URLs, also known as seed URLs. These seed URLs are typically provided by the search engine or can be manually specified.


Fetching the Web Page: The crawler fetches the content of the seed URL and sends an HTTP request to the web server that host the page and retrieves the HTML or any other relevant content from it.


Analyzing the HTML: Once the crawler has obtained the web page's HTML, it analyzes the document to extract various components such as links, text content, meta tags, and other relevant information.


Extracting Links: The crawler extracts all the hyperlinks present in the analyzed HTML. These links serve as a track or directive to other web pages that the crawler will visit next.


Queuing URLs: The extracted links are then added to a queue, which serves as a "to-do" list for the crawler. These URLs will be visited in the subsequent crawling process.


Visiting Linked Pages: The crawler chooses a URL from the list and visits the associated webpage after identifying it. It retrieves the content, analyzes it, and extracts any new links discovered there. The crawler follows the links to find and discover new pages as it continues to iteratively carry out this process.


Crawling Depth and Limits: Crawlers often have a maximum crawling depth or a limit on the number of pages they can visit. This helps to ensures that the crawler focuses on a specific scope of the web and prevent infinite loops.


Storing Collected Data: During the crawling process, the crawler can collect various data from the visited pages, such as the page content, metadata, URL structure, and other relevant information. This data is typically stored in a database or indexed for later retrieval and analysis.


Following Robots.txt and Crawl Delays: Web crawlers typically honor the rules defined in a website's robots.txt file, which specifies which parts of the site can be crawled and which should be excluded. Additionally, crawlers may introduce crawl delays between requests to avoid overloading servers and respect the website's policies.


Indexing and Ranking: The information collected by the crawler is used by the search engine to index the web pages and determine their relevance and ranking in search results. Other factors, such as page quality, backlinks, and user signals, also influence the ranking process.


As web crawling is a very important part of page ranking so, rarely crawled pages won't display any updated updates that may otherwise improve SEO. You need to get in touch with the best digital marketing agency in US, so that you may know how to hold the best practices. SEO can be enhanced by ensuring that pages are updated and regularly crawled, especially for content that must be indexed quickly.