What is Interaction to Next Paint ?

All we need to know about Interaction To Next Paint (INP)

Interaction to Next Paint (INP) 8s an experimental metric that evaluate responsiveness. (INP) observers the latency of all interactions a user has made with the page, and reports a single value which all interactions were below. A low INP means the page was consistently able to respond quickly to all of the users interactions.

The usage data of chrome shows' that 90% of the user's time on a page is spent after it loads. Thus precautions of responsiveness throughout the page recycle is important. This is what the INP metric assesses. Good responsiveness means that the page is responding quickly to Interactions made with it.

The goal of INP is to ensure the time from when a user initiates an interaction until the next frame is painted as short as possible, for all most all interactions the user makes. 

Let's see few points which need to be kept in mind.

What's INP?

​What's a good INP value.

​How to measure INP.

​How to improve INP.

​INP aims to represent a page overall responsiveness by measuring all click, tap, 

and keyboard interaction made with a page.

An interaction is an group of event handles that fire during the same logical user gesture. An Interactions latency consist of the single longest duration of a group of event handlers that drives the interaction.

Pinning the labels such as 'good' or 'poor' on a responsiveness metric is different. On one  hand you want to encourage development practice that priorities good responsiveness.

On the other hand you must account for the fact that there's considerable variability in the capabilities of the device people used to set achievable development expectations.

It is also possible that a page can return no INP value this can happen for the number of reason.

The page was uploaded but, the users never clicked, tapped or pressed a key on their keyboard.

​The page was loaded but the user interacted with the page using gesture tha did not involved clicking, tapping, or using the keyboard.

​ The page is being accessed by a bot such as a search crawler or headless browser that has not been scripted to interact with the page.

​If your website is reporting INP values that fall outside the good threshold, you'll want to figure out what you can do to improve. High INP values are usually indicative of high reliance on JavaScript, or other non JavaScript main thread work that may run concurrently with users interactions.