First Input Delay (FID)

First Input Delay (FID) is a performance metric used to measure a user’s interaction with a webpage. It represents the time it takes between a user’s first interaction with the page, such as clicking a button or entering information into a form, and the browser’s response to that input. FID is an important metric because it measures a user’s perception of the page’s responsiveness. A fast FID score indicates that the page is responding quickly to user input, providing a positive user experience. On the other hand, a slow FID score indicates that the page may be unresponsive, resulting in users becoming frustrated and potentially abandoning the site.