Poor Interaction to Next Paint (INP)

INP measures how quickly the page visibly responds after a tap, click or key press. Good is 200 milliseconds or less. Slow responses usually come from long JavaScript tasks blocking the main thread.

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Three parts of every interaction

Each interaction has an input delay, a processing time and a presentation delay. Measuring which part is slow tells you what to fix.

Diagnose it

Symptoms, checks and fixes

Common symptoms

An "INP issue" in the Core Web Vitals report.
Menus, filters or form buttons react late on phones.

Checks to run

Diagnostic checks
Check	How to tell	Fix
Is the main thread busy when people tap?	Record an interaction in browser developer tools and look for long tasks before the handler runs.	Defer or break up work that runs during page load.[1]
Do event handlers do too much?	Check how long the click or input handler takes to finish.	Do only what is needed for the next visual update, and move the rest to a later task.[1]
Is rendering the bottleneck?	Look for a large DOM or big chunks of HTML rendered in JavaScript after the interaction.	Reduce DOM size and avoid rendering large amounts of HTML on the client.[1]