FID

ELI5 — The Vibe Check

FID measured how long it took for the browser to react after you first clicked something. It was a Core Web Vital until 2024, when Google replaced it with INP. FID was like asking 'how frozen is the page when it first loads?' INP asks that question for every interaction, which is more useful.

Real Talk

First Input Delay (FID) was a Core Web Vital measuring the delay between a user's first interaction (click, tap, key press) and the browser's response. It was replaced by INP in March 2024 as the primary interactivity metric in Core Web Vitals. FID only measured the first interaction and ignored subsequent ones.

When You'll Hear This

FID was deprecated in favor of INP in March 2024.,If you still see FID in old reports, that's the legacy metric.,INP is more comprehensive than FID as it covers all interactions.