Interaction to Next Paint (INP) is one of Google’s three Core Web Vitals metrics, measuring how quickly a page visually responds after a user interacts with it — clicking a button, tapping a menu, or typing into a field. It replaced First Input Delay (FID) as an official Core Web Vital.
Google considers an INP under 200 milliseconds to be a good user experience. Slow INP scores are often caused by heavy, unoptimized JavaScript that blocks the browser’s main thread, preventing it from responding promptly to user actions.
Improving INP typically involves breaking up large JavaScript tasks into smaller chunks, deferring non-essential scripts, and reducing the overall amount of JavaScript that needs to execute in response to common user interactions.
INP optimization is included in our Technical SEO service, particularly for interactive, JavaScript-heavy websites.