what is INP?
INP in its literal translation means interaction with the next painting. That is, the time it takes for the user to be able to interact with all the pieces of content after they have been displayed (painted). As far as I understand, this new metric will no longer limit the measurement to the first painting, which caused many to optimise the first painting (FCP) and neglect or neglect the rest of the page elements up to the footer.
INP will officially become a stable Core Web Vital metric in March 2024.
This is how INP values are supposed to be interpreted.
Up to 200 milliseconds is considered good, from there up to 500 Google considers it needs improvement and anything over 500ms is a poor experience.
what needs to be done?
For SEO purposes, as this is a major metric that will affect your search engine ranking it is a given that it needs to be addressed although nothing new needs to be done. It is enough to extend the usual actions to all the elements of the page, something that most of us who take optimisation seriously (not just to keep Google happy) already try to do.
Among those common tasks are taking care of scripts that slow down loading, improving the response time and behaviour of HTML and CSS and, of course, of our server whenever possible.
Now it will be necessary to take clues as to which of the resources that are used fatten the INP and continue to lighten the DOM. It will not always be possible to solve what Google seems to tell us is a “problem” (these are recommendations, not obligations). What’s more, sometimes their own tools or products alter these results, as is the case with Adsense ads and CLS.
And remember not to get too obsessed because to have all these “traffic lights” in green you would have to build a website only with plain text.