Interaction to Next Paint, or INP, is a Core Web Vitals metric that measures how quickly a page responds visually after a user interaction such as a click, tap, or key press. In simple terms, it shows the delay between a user action and the moment the page updates on screen. A good INP is 200 milliseconds or less, 200 to 500 milliseconds needs improvement, and above 500 milliseconds is poor.
Why Interaction to Next Paint matters for SEO and UX
INP matters because it reflects real user experience. A page can load quickly at first but still feel frustrating if buttons, forms, filters, or menus react slowly. When users try to interact and nothing appears to happen right away, they are more likely to leave, stop converting, or lose trust in the site.
For SEO, INP is part of Google’s Core Web Vitals framework, which means it helps Google evaluate page experience. It is not the only ranking factor, but it is important because it connects technical performance with usability. For marketers and site owners, improving INP can support better engagement, stronger conversion rates, and fewer abandoned sessions.
How INP works
INP looks at the latency of user interactions across a page visit and reports a value that represents the worst or near-worst delays users experience. Unlike older responsiveness metrics that focused on a narrower slice of activity, INP gives a broader view of how responsive the page feels over time.
What can make INP worse
Common causes include heavy JavaScript, long-running scripts on the main thread, large third-party tools, complex event handlers, and rendering work that blocks the browser from updating the screen quickly. If the browser is busy processing code, it cannot paint the visual response fast enough.
How to improve it
Start by reducing unnecessary JavaScript, breaking up long tasks, delaying non-essential scripts, and simplifying interactive components. Review third-party apps, chat widgets, tag managers, and tracking scripts, since these often add interaction delays. Also test forms, menus, search boxes, filters, and mobile navigation because these are common problem areas.
Practical example of Interaction to Next Paint
Imagine an ecommerce category page with product filters. A shopper taps the “In Stock” filter, but the page does not visibly update for 700 milliseconds because several scripts are running and the filter logic is heavy. That interaction creates a poor INP signal. If the development team reduces JavaScript work, defers non-critical scripts, and makes the filter update faster, the page may respond in 150 milliseconds instead. The result is a smoother shopping experience and a better chance the user keeps browsing and buying.
For SEO beginners and in-house teams, the practical takeaway is simple: measure how fast your pages react after clicks and taps, then prioritize fixes on high-value templates such as product pages, lead forms, and navigation-heavy pages.