INP

What is INP?

INP, or Interaction to Next Paint, is a Core Web Vital metric that measures the responsiveness of a webpage to user interactions — specifically, the delay between a user's input (a click, tap, or keyboard press) and the next time the browser visually updates in response.

INP replaced FID (First Input Delay) as an official Core Web Vital in March 2024. While FID only measured the delay before the browser started processing the first interaction, INP measures the full response time of all interactions throughout the entire page visit — making it a more comprehensive measure of a page's overall responsiveness.

INP Thresholds and Fixes

Google's INP thresholds: Good (under 200 milliseconds), Needs improvement (200 to 500 milliseconds), and Poor (over 500 milliseconds).

Common causes of poor INP include: Long JavaScript tasks (large JS files that block the browser's main thread), Heavy rendering (pages with complex DOM structures or expensive CSS), and Third-party scripts (analytics, chat widgets, and ad scripts that consume main thread time).

Improving INP on Webflow sites: minimize and defer non-critical JavaScript, audit and remove or delay heavy third-party scripts via custom code settings, and use Webflow's native Interactions rather than heavy custom JS libraries where possible.

At Appsrow, we test INP scores using Google's PageSpeed Insights and Lighthouse as part of every project's pre-launch quality assurance.