INP (Interaction to Next Paint)
INP measures how long the page takes to show a visible response after the visitor interacts with it.
Also known as: interaction to next paint · responsiveness
It replaced the older FID metric, and it measures something more honest: not just the first interaction but the worst one across the visit.
Bad INP almost always means JavaScript is occupying the main thread. Long tasks have to be broken up; heavy work belongs in a worker or has to wait until the browser is idle.
Common questions
Does a 3D scene hurt INP?
It can, if the scene is set up on the main thread while the visitor is already clicking. Loading the scene progressively and after the interface is usable keeps the number down.
Is 200 ms strict?
It is achievable. The pages that fail it are usually carrying several third-party scripts rather than doing heavy work of their own.
How does this term apply to your work? Let us talk.
Get in touch