Virtual machines (VMs) are valuable tools in IT, particularly for cross-browser testing of web applications, as they simulate actual hardware and allow the emulation of different environments. They enable developers to work across multiple operating systems on a single workstation and provide a way to test applications on older systems, like Windows XP, without changing the current setup. VMs also offer a secure testing environment for complex software, protecting primary and secondary memory from crashes. Setting up a VM involves using software like VirtualBox, where an operating system's ISO file is installed on a virtual drive. For web application testers, VMs facilitate testing across various browsers and operating systems, including challenging environments like macOS, where browser compatibility issues often arise. Cloud-based VM solutions, such as LambdaTest, extend these capabilities by offering virtual environments online. Despite their slower speed and some limitations in hardware feature utilization, VMs are beneficial for running automated tests across isolated environments, making them an optimal solution for cross-browser testing. The article is authored by Arnab Roy Chowdhury, a UI developer and seasoned blogger.