Interaction to Next Paint (INP) is a new metric that Google uses to measure how quickly your website reacts to user interactions. It will become one of the Core Web Vitals metrics that impact Google rankings on 12 March 2024.

This article takes a look at what INP measures and what you can do to optimize it.

Interaction to Next Paint (INP) is a web performance metric that measures user interface responsiveness – how quickly a website responds to user interactions like clicks or key presses.

Specifically, it measures how much time elapses between a user interaction like a click or key press, and the next time the user sees a visual update on the page.

As you have understood by now INP is a check of how long it takes for the next paint process to complete. By paint process, can be anything that shows up on the screen. Maybe a popup a toast message or a dynamic search panel opening.

A site that has great INP you would find it doesn't have many animations in place and uses JavaScript (both first-party and third-party) to a minimum. Also, these scripts are loaded only for the pages that absolutely need them and not globally across the whole website.

You would often see that a site that has a high Total Blocking Time (TBT) and First Input Delay (FID) would also have a high INP score. This is mainly because these sites are loading a huge amount of javascript and external tools, ad scripts, tracking scripts and so much more on their website.

As a result, in any interaction you make on your website, first, a lot of JavaScript needs to be executed based on the events those JavaScripts are hooked to before the request can be performed and as a result, it increases the time required for the browser to paint the next object that it is supposed to do.

Any website that uses a lightweight theme without any JavaScript-based animations or doesn't rely on huge third-party scripts (e.g. ad scripts, analytics scripts) would see the best INP result along with lower TBT and FID as explained before.

Just to give you a perspective of things, take a look at this screenshot image to see one of many websites that is failing the INP test and how much render-blocking JavaScript they are using.

The best solution is to keep your website as lightweight as possible and not use unnecessary plugins. Ask your theme/plugin developers not to load unnecessary scripts globally across the website and only load them where it's absolutely needed.

Moreover, if you already have a website where you are running ads and other JavaScript-heavy things, unfortunately there isn't much that you can do to improve this unless these Ad Networks improve their JavaScripts to be super lightweight and not to add too much load to the webpage.

Even after INP gets added to Core Web Vital, even if you are failing INP, it is not going to drastically affect your ranking and search traffic. In the Google Search algorithm, there are thousands of variables based on which a page ranking is calculated.

Among all these variables, INP plays a very minuscule role. Imagine 1 point is reserved for Good INP out of 100. So, instead of stressing over this INP issue, you should focus more on creating quality content for your website, doing link buildings etc. as these would affect your search ranking more than just 1 point of INP.

All the information that we have provided above is based on our testing of thousands of websites checking them side by side to come up with a conclusion. But unfortunately as of now Google Page Speed Insight or any other tool doesn't give you any quick way to test exactly what's causing the INP issue on your website.

This is mainly because INP data is not part of the lab data and is only available under field data which is taken from the real world users. But we do sincerely hope that Google will soon release a tool to maybe point out the exact culprits behind INP issues. But for now, no such tool exists.