Crawling is the process search engines use to discover content on the web. Automated programs called crawlers (also known as spiders or bots) follow links from page to page, request URLs, and collect information about what they find. In simple terms, crawling is how a search engine learns that a page exists and gathers the raw data it needs before it can decide whether, and how, to show that page in search results.
For accuracy and clarity, it helps to separate crawling from indexing. Crawling is the act of finding and fetching pages, while indexing is the step where a search engine analyzes the content and stores it in a database for retrieval later. A page can be crawled but not indexed if it has a noindex directive, duplicate content, low value, or other issues. If you want important pages to be discovered reliably, focus on clear internal linking, a well maintained XML sitemap, sensible robots.txt rules, and fast, stable page performance so crawlers can access your content efficiently.