Measure the response to an interaction
Interaction to Next Paint, or INP, measures responsiveness to clicks, taps and keyboard input during a page visit. It considers the delay before the browser can present the next visual update. It is one of the Core Web Vitals.
Google’s guidance classifies an INP of 200 milliseconds or less as good, assessed at the 75th percentile of visits and separated by device type. INP is not simply the total time a server takes to finish a request. The web.dev INP guide explains the metric and its measurement.
Example: a menu responds late on a phone
Imagine a visually rich homepage that loads quickly but hesitates when a visitor opens the mobile menu. An animation or another script may be occupying the browser’s main thread just as the tap occurs. The customer taps again, unsure whether anything happened, and the delayed actions can produce confusing behaviour.
Investigate that interaction while the page is busy as well as after it settles. Reducing unnecessary work, dividing long tasks and prioritising immediate feedback can make the page feel more dependable. The goal is to preserve useful interaction while preventing decorative work from delaying a customer’s action.
How to use INP evidence
Start with real-user data when enough of it is available, then reproduce the affected journeys in a development environment. Check menus, filters, form validation and controls used after the initial page load. A homepage-only loading test cannot represent every interaction.
Keep the metric separate from the complete business transaction. A form may acknowledge a submit action quickly while an external service takes longer to finish processing. Both experiences matter, but the remedies differ. Missing field data is not evidence of a perfect score; smaller sites may need deliberate interaction testing while representative usage accumulates.
Common questions about interaction to next paint
Does smooth scrolling mean INP is good?
Not necessarily. INP observes click, tap and keyboard interactions rather than scrolling itself. Test the controls customers actually use.
Can a high Lighthouse score prove every interaction is fast?
No. A loading test covers a particular run and may not exercise the relevant controls. Investigate realistic journeys and available field measurements alongside laboratory results.
Related definitions
- Core Web Vitals — A set of user experience measures covering loading, responsiveness and visual stability. The current metrics are Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift.
- JavaScript — A programming language used for interactive website behaviour and application logic. Essential content should remain accessible if an optional visual feature fails.
- Largest Contentful Paint — A loading measure that reports when the largest visible content element is rendered. Large hero images, slow delivery and render-blocking resources can delay it.
- UX design — User experience design: understanding people’s tasks and shaping the structure, content and interactions that help them complete those tasks.
Related SEO guides
Responsiveness matters most when a visitor opens navigation, uses a filter or attempts to submit an enquiry.
For help connecting these decisions with your website, explore our SEO services or start with an SEO audit.
Put it into practice
Explore our technical seo service or talk with Refined IT about applying this to your website or business systems.