Google replaces First Input Delay (FID) metric with Interaction to Next Paint (INP): What does this mean for web developers?

Google has announced that its new Interaction to Next Paint (INP) metric will officially replace First Input Delay (FID) as a Core Web Vital starting March 12. INP measures the time from when a user interacts with a page (for example, clicks a button) to when the browser can display the changed pixels on the screen. This aims to measure aspects of interaction that the FID did not capture.

"FID, which measured the time to first render after the first user interaction, was introduced in 2018 as part of Google's Web Vitals initiative. Web Vitals provides metrics to help web developers optimize critical aspects of the user experience."

🚀 Over time, Google realized the limitations of FID in measuring engagement, leading to the introduction of INP as an experimental metric in May 2022. After a transition period as a "pending metric", Google confirmed that INP will officially replace FID in March.

• 📌 As the transition to INP approaches, developers should check that their website's INP meets the "good" threshold, which reflects performance at the 75th percentile of page loads.
• 📌 For sites that currently do not reach the "good" INP threshold, Google recommends taking the following steps to optimize the transition.

🚀 First, you need to evaluate your current INP performance using tools like PageSpeed ​​Insights and the Chrome User Experience Report. Then you need to identify problems that are slowing down INP, such as long JavaScript tasks, too much main thread activity, or a large DOM.

"Next, you need to optimize the problem areas by following Google's optimization guidelines. This may include optimizing JavaScript, reducing input lag, simplifying the DOM structure, or improving CSS selectors."

🚀 Implementing Google INP as Core Web Vital can impact web development and user experience in several ways:

• 📌 Site search engine rankings and user engagement may depend on INP scores because Google uses Core Web Vitals in its ranking algorithm.
• 📌 Web development practices may change, focusing more on optimizing interoperability, which may require changes to application architecture and code.
• 📌 Performance monitoring tools and strategies may need updating to track and analyze new INP metrics.