Mobile Friendly Test is a tool used to evaluate the mobile responsiveness of a website. It allows website owners and developers to assess how their website looks and performs on various mobile devices, including smartphones and tablets. The tool checks whether the website's design and layout are optimized for mobile devices, as well as whether the website loads quickly on mobile devices.

The Mobile Friendly Test tool works by analyzing the website's HTML, CSS, and JavaScript code to determine whether it meets the criteria for mobile-friendly design. The tool examines factors such as text readability, button size, touch elements, image and video display, and overall responsiveness to user interaction.

The tool typically provides feedback in the form of a report, highlighting areas where the website needs improvement to better cater to mobile users. The report may include suggestions such as using responsive design, optimizing images, compressing files, or reducing page load times.

Mobile Friendly Test tools are provided by various organizations, including Google, Bing, and other web development companies. They are often free to use and can be accessed online, making them a convenient resource for website owners and developers to assess the mobile-friendliness of their website.