INP (Interaction to Next Paint)

What Is INP?

Since INP replaced First Input Delay as a Core Web Vital, the responsiveness of your website is an official ranking factor. Especially e-commerce sites and interactive web applications with filters, shopping carts, and forms are affected, as many user interactions happen there. A poor INP score frustrates your visitors and costs you rankings at the same time — optimization pays off doubly.

INP (Interaction to Next Paint) is a Core Web Vital metric from Google that measures the responsiveness of a web page to user interactions. Specifically, it captures the time between the moment a user interacts with a page (click, key press, touch) and the moment the browser displays the visual changes. This metric has been part of Google Core Web Vitals since 2023 and directly influences ranking in search results.

The mechanism is technically precise: when a user clicks a button, for example, the clock starts. It runs until the browser displays the next visual update. A long INP time (over 200 milliseconds) means the page is sluggish — the user waits until something visibly changes. This is often a sign of slow JavaScript functions, inefficient DOM access, or CPU bottlenecks. Google prefers pages with an INP below 100 milliseconds — this is rated as “Good.”

For optimization, website owners should review and optimize their JavaScript, especially for mobile devices. Tools like Google PageSpeed Insights and the Chrome DevTools Performance tab show where response times are slowing down. Common causes are overly large JavaScript files, inefficient event listeners, and main thread blocking. For e-commerce sites and interactive web applications, INP is especially important because users interact a lot with filters, shopping carts, and forms. Improving INP leads not only to better rankings but also to more satisfied users.