INP Takes Over as a Core Web Vital
Interaction to Next Paint (INP) is now a stable Core Web Vital, officially replacing First Input Delay (FID). The change is a major step in how Chrome measures interaction responsiveness, addressing limitations in the older FID metric.
From today, Chrome’s Core Web Vitals tools—including PageSpeed Insights, the CrUX Dashboard, and the Web Vitals extension—will treat INP as the primary responsiveness metric. PageSpeed Insights’ Core Web Vitals assessment now evaluates INP instead of FID. Some tools may also begin showing deprecation notices for FID to signal its removal.
FID Removal Schedule
Chrome is formally deprecating FID support now that INP has taken its place. Developers have until September 9, 2024 to fully transition. This deadline is critical for anyone consuming the Chrome User Experience Report (CrUX) or PageSpeed Insights APIs: applications processing FID data from these services will break on that date. The change will be breaking in the latest API versions, with no major version bump.
Finding and Fixing INP Issues
The INP optimization collection is a central resource for documentation on the metric, local measurement techniques, real-user monitoring, and case studies. A practical workflow for addressing INP problems on your site looks like this:
Read the canonical INP documentation to understand how responsiveness is measured.
Assess your real-user data. To be considered good, at least 75% of INP experiences should respond to input in under 200 milliseconds. If your site passes this threshold, no action is needed.
- Use PageSpeed Insights or the Core Web Vitals report in Search Console (if your site is in the CrUX dataset).
- Check if your analytics provider supports INP monitoring.
- Build a custom solution with web-vitals.js.
Instrument your site to collect diagnostics—such as which page element was interacted with and what made the interaction slow—to identify opportunities for improvement.
Reproduce slow interactions in Chrome DevTools to inspect the offending code.
Optimize the interaction path by minimizing work: break up long JavaScript tasks, cut unnecessary JavaScript, and avoid large rendering updates.
Verify the fix locally and monitor real-user data to confirm sustained improvement.
For troubleshooting, queries tagged interaction-to-next-paint on Stack Overflow are a good place to seek help. The move to INP concludes work that started with a proposal for a better responsiveness metric in 2021, with community feedback shaping the final implementation.
