The diagram below shows a high-level walk-through of a search engine.

▶️ Step 1 - Crawling Web Crawlers scan the internet for web pages. They follow the URL links from one page to another and store URLs in the URL store. The crawlers discover new content, including web pages, images, videos, and files.

▶️ Step 2 - Indexing Once a web page is crawled, the search engine parses the page and indexes the content found on the page in a database. The content is analyzed and categorized. For example, keywords, site quality, content freshness, and many other factors are assessed to understand what the page is about.

▶️ Step 3 - Ranking Search engines use complex algorithms to determine the order of search results. These algorithms consider various factors, including keywords, pages' relevance, content quality, user engagement, page load speed, and many others. Some search engines also personalize results based on the user's past search history, location, device, and other personal factors.

▶️ Step 4 - Querying When a user performs a search, the search engine sifts through its index to provide the most relevant results.