FID

What does FID stand for?

First Input Delay

First input delay (FID) is a metric used to measure the responsiveness of a webpage. It is one of three core web vitals Google introduced in 2020 to objectively analyze website user experience (UX).

Specifically, FID measures the time from the user’s first interaction with a page to the beginning of the browser’s response. For example, if a user clicks a checkbox and the browser responds in half a second, the FID for that page would be 500 ms. It’s important to note that FID doesn’t measure load time or processing time — only the first delay in user interaction.

Research suggests that users can perceive input delays as short as 100 ms and that these delays have a negative impact on user experience. Developers are encouraged to reduce the FID of webpages by leaving the main thread available to respond to input as much as possible. One of the most effective ways to improve FID is to reduce or eliminate render-blocking resources like scripts and stylesheets.

Example

By removing unneeded dependencies, we reduced FID across the website.
Timeline showing an input delay as a webpage loads

Timeline showing an input delay as a webpage loads

Related Slang

Categories

Updated June 11, 2021

FID definition by Slang.net

This page explains what the acronym "FID" means. The definition, example, and related terms listed above have been written and compiled by the Slang.net team.

We are constantly updating our database with new slang terms, acronyms, and abbreviations. If you would like to suggest a term or an update to an existing one, please let us know!