WebVitals INP Score: Monitoring and Optimizing User Experience with Pubperf

Web performance plays a critical role in providing a positive user experience on the web. To ensure that websites are responsive and interactive, web developers and publishers need to monitor and optimize various performance metrics. One such important metric is the Interaction to Next Paint (INP) score, which has recently gained support and is now integrated into Pubperf analytics.

INP is a Core Web Vital metric that is set to replace First Input Delay (FID) in March 2024. It focuses on assessing a page's responsiveness by measuring the latency of all user interactions throughout a user's visit to a website. The INP score provides valuable insights into how well a page can respond quickly to user actions.

WebVitals INP

Traditionally, metrics like FID only considered the first interaction on a page. However, INP takes into account all interactions, ensuring a more comprehensive evaluation of a website's responsiveness. By considering the latency of click, tap, and keyboard interactions, INP captures the overall user experience by identifying the longest interaction observed while ignoring outliers.

The calculation of the INP score involves measuring the duration of event handlers associated with an interaction, starting from the initiation of the interaction until the next frame is presented with visual feedback. The goal is to minimize this time gap and provide immediate visual feedback to users, indicating that their actions are being processed by the website.

To determine the quality of a website's responsiveness, INP scores are categorized into three thresholds:

• Good responsiveness: INP below or at 200 milliseconds.
• Needs improvement: INP above 200 milliseconds and below or at 500 milliseconds.
• Poor responsiveness: INP above 500 milliseconds.

These thresholds serve as guidelines for developers to set achievable development expectations and prioritize optimizations accordingly.

Monitoring and optimizing the INP score is crucial for delivering exceptional user experiences. Publishers can leverage tools like Pubperf analytics, which now supports INP score measurement. Pubperf analytics provides real-time insights into INP values and other performance metrics, allowing publishers to identify slow interactions and take proactive measures to enhance their website's responsiveness.

Measuring the INP score can be done both in the field and in the lab. Field data obtained through Real User Monitoring (RUM) provides valuable information about specific interactions responsible for the INP score, enabling developers to pinpoint areas that require optimization. Additionally, Chrome User Experience Report (CrUX) offers origin-level and page-level INP data for websites that qualify.

In the lab, developers can reproduce slow interactions by following common user flows and testing interactions during crucial stages of page loading. By combining field data insights with lab testing, developers gain a comprehensive understanding of slow interactions and can implement optimizations effectively.

Improving the INP score involves various strategies, such as optimizing event handler performance, reducing main thread workload, and prioritizing critical rendering paths. The process requires a deep dive into the specific interactions causing delays and addressing performance bottlenecks accordingly.

The INP score is a vital metric for assessing a website's responsiveness and optimizing user experiences. With Pubperf analytics now supporting INP score measurement, publishers have a powerful tool at their disposal to monitor and optimize INP. By prioritizing performance enhancements based on INP insights, web developers can deliver highly responsive and interactive websites, resulting in improved user satisfaction and engagement.

How people use Pubperf:

SEO Agency uses pubperf to audit the page speed of the client's website and optimise based on the recommendations. Then generate an ongoing report for your clients. They are able to show the job they have done on the website.

Digital publishers and agencies use pubperf to manage the website performance for a large number of websites. It is important to have a fast website, but it is a pain to keep running page speed report on tons of websites they own. They also use Pubperf to track the performance of prebid.js.