Learn · Performance & optimization

What is INP (Interaction to Next Paint)?

INP measures responsiveness: how quickly the page reacts visually after you tap, click, or type. It replaced the older FID metric in March 2024 and looks at interactions across the whole visit, not just the first. The target is under 200 milliseconds. It's the most commonly failed vital in 2026.

A poor INP feels like lag: you tap a button and nothing happens for a moment. The usual cause is heavy JavaScript blocking the browser from responding. Reducing and breaking up that work, and deferring non-essential scripts, is how you improve it.

INP matters most on interactive sites and apps, where users click and type a lot. Because it captures the whole session, a single slow interaction (like opening a heavy menu) can drag the score down, so every key interaction needs to stay quick.

Updated July 2026

Learning Center More on performance & optimization

What are Core Web Vitals?
Core Web Vitals are Google's three metrics for real-world page experience: LCP (loading speed), INP (responsiveness), and CLS (visual stability). As of July 2026 the "good" targets are LCP under 2.5 seconds, INP under 200 milliseconds, and CLS under 0.1, measured on real visitors at the 75th percentile.
What is page weight, and why does it matter?
Page weight is the total size of everything a page downloads: images, scripts, styles, fonts, and video. Heavier pages take longer to load and cost visitors more data, especially on mobile. Keeping page weight down is a direct lever on speed and on how many people stick around.
What is LCP (Largest Contentful Paint)?
LCP measures how long it takes for the largest visible element (usually the main image or heading) to load and appear. It's the closest single number to "how fast does this page feel to load." The target is under 2.5 seconds for the good rating, measured on real visitors.
What is CLS (Cumulative Layout Shift)?
CLS measures visual stability: how much the page unexpectedly jumps around as it loads. The target is under 0.1. You've felt bad CLS when you go to tap a button and an image or ad loads above it, pushing everything down so you tap the wrong thing.
Why does website speed matter for business?
Speed affects money directly. Faster sites keep more visitors, convert more of them into customers, and rank better in search. Study after study shows that as load time rises, people leave and sales drop. A slow site quietly loses revenue before anyone reads a word of your content.
What is a CDN, and do I need one?
A CDN (content delivery network) is a network of servers around the world that store copies of your site's files and serve them from the location nearest each visitor. That shorter distance means faster loading. Most sites with a global or growing audience benefit, and many hosts now include one.

Want this built, not just explained?

Start the conversation

What is INP (Interaction to Next Paint)?

What are Core Web Vitals?

What is page weight, and why does it matter?

What is LCP (Largest Contentful Paint)?

What is CLS (Cumulative Layout Shift)?

Why does website speed matter for business?

What is a CDN, and do I need one?

Want this built, not just explained?