Interaction to Next Paint (INP)

Interaction to Next Paint is a new CWV metric that has replaced FID. It measures the delay between a user’s action, such as clicking a button or typing in a field, and the web page’s visual response to that action.

Earlier FID only used to focus on the initial delay before the browser begins processing the user’s first interaction, while INP measures the entire user experience, capturing the time it takes for the browser to not only acknowledge user interaction but also process it and display the visual response on the screen.

The following diagram shows the difference between now deprecated metric FID and INP.

A page with INP score of 200 milliseconds or below is considered to have good responsiveness. Anything above it needs improvment.

Read more about INP – https://web.dev/articles/inp

To visualise what interaction delay is and how it affects INP, click here.

We have our own blog that describes in details practices we use to identify and optimise INP – https://rtcamp.com/blog/all-about-interaction-to-next-paint/