Interaction to Next Paint (INP) accurately measures the real-world responsiveness of your web pages by analyzing every interaction your users have with your site.
This metric analyzes the response time between a user’s click and the result being displayed on the screen, specifically identifying the times when your site takes the longest to respond.
Unlike First Input Delay (FID), which only considers the first interaction, INP covers all interactions, thus providing a more reliable overview of responsiveness.
To ensure a flawless user experience, aim for an NPI value under 200 milliseconds, which is the time it takes for an eyelash to blink. Google now includes NPI in its ranking criteria: a fast and responsive page improves your natural referencing.
How does INP differ from First Input Delay (FID)?
Let’s explore the differences between INP ( Interaction to Next Paint) and FID (First Input Delay), two essential responsiveness metrics. FID measures the delay between a user’s first interaction and the browser’s response. Its main limitation? It only captures a single interaction, ignoring everything else in the on-page experience.
The INP, on the other hand, evaluates all interactions during the lifetime of a page, particularly identifying the slowest ones. Thus, it measures the total time from the start of an interaction until the browser displays the result. This provides a more complete and accurate view of the user experience.
Replacing FID with INP in Google’s Core Web Vitals aims to improve the perception of web page responsiveness. This decision makes sense: FID focuses on a single moment, while INP covers the continuum of interaction, encouraging development practices focused on optimizing overall responsiveness.
Why is INP crucial for user experience?
NPI, or Interaction to Next Paint, plays a key role in user experience because it measures the responsiveness of your website. It evaluates the time it takes for the site to react to an interaction, such as a click, and display the result. A low NPI ensures smooth browsing and smooth latency.
This responsiveness captures visitors’ attention and encourages them to explore your site. This speed of execution improves customer satisfaction while reducing bounce rates— a definite competitive advantage for your online presence.
What factors influence the measurement of INP?
Four main factors impact the measurement of INP:
- The complexity of JavaScript code plays a major role. Heavy code can delay the browser’s response to user interaction.
- The number of interactions on a page directly influences the calculation of the NPI. For pages with few interactions, the NPI is based on the longest interaction. For pages with high interactions, Google analyzes the 98th percentile, in other words, it focuses on the slowest interactions.
- Event processing also influences, each interaction is made up of several events, and the latency of the INP depends on the time taken by these events to execute.
- Server performance and user connection speed impact the site’s response time.
What are the methods to measure INP effectively?
How can you effectively measure Interaction to Next Paint (INP)? Start by equipping yourself with the right web performance analysis tools; they’re essential for assessing this metric.
These tools analyze on-page interactions and measure overall responsiveness, expressed in milliseconds.
Note: an NPI of less than 200 ms is considered optimal for your site.
Using the Chrome User Experience Report (CrUX) provides an overview of real-world user performance. Also, consider lab testing to simulate realistic user interactions. This method allows you to replicate real-world browsing conditions and accurately identify slowdowns.
The data collected will allow you to precisely target your optimizations. For an even more comprehensive assessment, focus on analyzing the NPI under real-world conditions.
The result? Precise and effective improvements that will guarantee an impeccable user experience.
What tools should you use to measure the NPI on your website?
To measure the NPI on your site, here are the best tools at your disposal:
- Start with the Site Kit by Google plugin for WordPress, which centralizes data from multiple services to optimize performance.
- For a more in-depth analysis, head to PageSpeed Insights, which provides you with a free, detailed diagnosis of the INP.
- On the development side, Chrome DevTools is the benchmark for tracking your metrics in real time.
- WebPageTest provides a global view of performance, taking into account international variations.
- Chrome UX Report (CrUX) measures performance based on real user data, ensuring accurate analysis.
- Google Search Console allows you to observe your site’s performance in detail.
What are the impacts of a bad INP on SEO?
Poor NNP (Interaction to Next Paint) negatively impacts website rankings. Poor responsiveness means high response times, which degrades the user experience. Visitors are less likely to stay on a slow site, which increases the bounce rate. These negative behaviors are strong signals for search engines.
This reality has not escaped Google: performance measurement is now part of Core Web Vitals, these key indicators for the search engine. This criterion significantly influences your SEO.
A response time exceeding 500 ms penalizes your ranking. To optimize your INP, simplify your JavaScript code and optimize your site’s overall performance.
What strategies can improve INP?
To optimize INP, focus on reducing reliance on JavaScript code, which is often a source of slowdowns. One effective strategy is to reduce Total Blocking Time (TBT) by removing unnecessary code and adopting code splitting to load scripts asynchronously. Use tools like Chrome DevTools to identify long-running tasks and slow third-party scripts.
Adopt the postTask API to better prioritize tasks, and reserve non-essential tasks for times when the browser is idle, using requestIdleCallback. Also, optimize DOM size to avoid slowdowns due to complex rendering.
Using Web Workers allows some tasks to be moved off the main thread, reducing blocking.
