What is First Input Delay (FID)?
First Input Delay (FID) is a user-centric metric that measures the time it takes for a web page to respond to a user's first interaction. This includes clicks, taps, or keyboard input from the user.
FID is an important metric because it helps measure how responsive and interactive a website or web application is. A long FID can lead to frustration for users, causing them to abandon the site and seek alternatives.