A headless browser operates without a graphical user interface, allowing for efficient browser automation by saving resources typically used for rendering and displaying web pages. While not sufficient alone for end-to-end testing or web scraping, headless browsers can be effectively utilized with browser automation tools that simulate human interactions on webpages. The guide explores various headless browser libraries such as Playwright, Selenium, Puppeteer, Cypress, chromedp, Splash, Headless Chrome, and HTMLUnit, detailing their features, supported programming languages, and limitations. Each library offers distinct advantages, such as cross-platform support or specific automation capabilities, making the choice dependent on the project's programming requirements and goals. Despite the capabilities of these libraries, anti-bot technologies may still hinder scraping operations, though solutions like Bright Data's Scraping Browser offer comprehensive features to bypass such limitations.