A web scraper is a tool or software designed to extract data from websites. It works by sending requests to a web page, retrieving the HTML content, and then parsing that content to find specific information. This process allows users to gather data for various purposes, such as market research, price comparison, or content aggregation. Web scrapers can be programmed to navigate through multiple pages and collect data systematically. They are often used in conjunction with programming languages like Python or JavaScript, utilizing libraries such as Beautiful Soup or Scrapy to simplify the extraction process.