PERFORMANCE · SEO GLOSSARY

INP (Interaction to Next Paint)

The Core Web Vital that measures a page's responsiveness to user interactions — replacing FID in March 2024 as a Google ranking signal. Good INP is under 200ms.

Definition

Interaction to Next Paint (INP) measures the time from a user interaction (click, tap, or keyboard press) until the next frame is painted that reflects that interaction. It replaced First Input Delay (FID) as a Core Web Vital ranking signal in March 2024. INP captures the overall responsiveness of a page throughout its lifecycle — not just the first interaction like FID did, but any interaction. The INP score is the worst-case interaction latency (at the 98th percentile) during a page session. Thresholds: Good ≤200ms, Needs Improvement 201–500ms, Poor >500ms. INP is fundamentally different from FID: FID measured only the delay before the browser started processing the first input; INP measures the full round-trip delay from interaction through processing to the next visual update, and it tracks all interactions during the page session.

Why it matters for SEO

INP is a Core Web Vital and a Google ranking signal as of March 2024. Sites with Poor INP (>500ms) will see this factored into the Page Experience ranking signals. The shift from FID to INP is significant: FID was easy to "pass" by deferring JavaScript, because it only measured delay before the first input handler fired. INP is harder to pass because it measures whether the UI actually updates visually after an interaction — catching cases where the main thread is blocked by long tasks, heavy re-renders, or synchronous API calls during the interaction handling. Common INP culprits: long tasks blocking the main thread, heavy React/Vue component re-renders triggered by state changes, third-party scripts that block interaction processing, and non-virtualized long lists.

How DeepSEOAnalysis checks this

INP comes from real CrUX field data — actual Chrome users' interaction latency aggregated over 28 days. The audit pulls the p75 INP value for the URL from the CrUX API and reports it against the Good/Needs Improvement/Poor thresholds. Unlike Lighthouse, which doesn't measure INP in lab mode (it's a real-user metric), the CrUX value reflects what real visitors experience. Pages without sufficient CrUX data (low traffic) show "data not available" for INP.