A crawler is a kind of automated program used by search engines like Google, Bing, and Yahoo to discover, scan, and index websites. Spiders or bots have crawlers that follow a hypertext link from one page to another. It keeps all data information about the content and structure of the website, its updates, and other things. This data helps build search engine indexes, which determine how pages appear in the results of search engines. Efficient management of crawlers requires good configurations of the architecture of the website, robots.txt files for guidelines on what crawlers can view, and fast loading speed. A better understanding of crawler behaviour enhances SEO performance through correct indexing of vital pages.