Cross-browser testing is crucial to ensure a website's compatibility across different browsers and rendering engines, which can display content uniquely due to their distinct architectures. The main issue arises from the varying market shares of rendering engines such as Blink (used by Chrome, Edge, Opera, Vivaldi, Brave), Webkit (found in Safari and Apple devices), Gecko (mostly found in Firefox). Moreover, browsers come with multiple versions, and older versions may outnumber the latest ones, leading to potential compatibility issues. Rendering engine compatibility issues can be categorized into HTML and CSS rendering problems, JavaScript compatibility issues, font and image rendering problems, and differences between various browser versions. To address these challenges, Sauce Labs offers a unified test platform that allows users to detect and diagnose issues for both web and mobile applications across every part of the development lifecycle, saving time and improving the overall user experience.