Core Web Vitals · AuditJet Glossary
FID (First Input Delay)
The time from when a user first interacts with a page to the time when the browser is actually able to begin processing event handlers in response to that interaction.
FID was the Core Web Vital measuring interactivity from March 2020 to March 2024 when it was replaced by INP. FID only measured the first interaction's input delay, while INP measures all interactions throughout the page lifecycle. Teams upgrading from FID to INP often see different scores because INP includes all interaction delays.
Related terms
A Core Web Vital that assesses overall responsiveness by observing the latency of all qualifying interactions throughout the entire page lifecycle and reporting the worst-case value.
The total time between First Contentful Paint and Time to Interactive during which the main thread was blocked for long enough to prevent input responsiveness.
A JavaScript task that takes longer than 50ms to complete and blocks the browser's main thread, preventing user interaction.
Frequently asked questions
What is FID (First Input Delay)?
The time from when a user first interacts with a page to the time when the browser is actually able to begin processing event handlers in response to that interaction.
How does AuditJet measure FID (First Input Delay)?
AuditJet runs automated Google Lighthouse audits that surface FID (First Input Delay) scores alongside actionable fix guidance. You can track FID (First Input Delay) trends across all your pages and receive alerts when the metric regresses.
Monitor FID continuously
AuditJet tracks Core Web Vitals on a schedule with revenue impact alerts — powered by Google Lighthouse and Google PageSpeed Insights.
Start Free