Google’s recent switch from First Input Delay (FID) to Interaction to Next Paint (INP) as a key Core Web Vital has significant implications for website owners and developers. This change emphasizes the importance of overall page responsiveness rather than just the initial user interaction. Let’s dive into why this switch matters and how it affects you.

What is INP?

Interaction to Next Paint (INP) measures the total time between a user’s interaction (like a click or keypress) and the next paint on the screen, showing a visual response to that interaction. Unlike FID, which only measures the delay of the first interaction, INP considers all interactions within a session and reports the longest delay. This makes INP a more comprehensive metric for assessing user experience.

Why Google Switched from FID to INP

1. Holistic View of User Experience:

   • FID focuses solely on the first interaction, which may not accurately represent the overall user experience. INP accounts for every interaction, providing a more detailed picture of a page’s responsiveness throughout a user’s session.

2. User-Centered Approach:

   • INP is designed to be more user-centric. It evaluates how quickly a page responds to all user actions, not just the initial one, aligning more closely with how real users perceive performance.

3. Challenges with FID:

   • Most websites had already optimized for FID, making it less effective for differentiating site performance. INP presents a new challenge and encourages further optimization to improve user experience across the board.

Key Differences Between FID and INP

• Scope of Measurement:

  • FID measures the delay before the browser is ready to respond to the first interaction.

  • INP measures the total time from interaction to visual response for all interactions, providing a more comprehensive assessment.

• Reporting:

  • FID is reported once at the beginning of a session.

  • INP updates continuously, reflecting the worst interaction time recorded during a session.

• Difficulty to Pass:

  • INP scores are generally harder to achieve than FID scores, as optimizing all interactions is more challenging than focusing on just the first one.

Practical Implications for Website Owners

1. Focus on User Experience:

   • Optimizing for INP means ensuring that every interaction on your website is smooth and responsive. This involves improving not just the initial load time but the performance of all interactive elements.

2. Comprehensive Testing:

   • Unlike FID, which could be tested with a single interaction, INP requires extensive testing across various interactions. Tools that simulate user behavior and measure INP will be essential.

3. Continuous Improvement:

   • Achieving a good INP score involves ongoing efforts to refine and optimize your website. Regular updates and performance monitoring will be crucial to maintain high standards.

Tips for Optimizing INP

• Reduce JavaScript Execution Time: Heavy JavaScript can delay interactions. Minimize and defer unnecessary scripts.

• Optimize Main Thread Work: Ensure that the main thread is not overloaded, allowing for quicker response times.

• Improve Rendering Performance: Use techniques like lazy loading and efficient CSS to ensure that the page paints quickly after an interaction.

• Monitor Real User Metrics: Use field data to understand how real users interact with your site and identify areas for improvement.

Conclusion

The shift from FID to INP underscores Google’s commitment to enhancing user experience on the web. By focusing on all interactions, INP provides a more accurate measure of how users perceive page performance. For website owners and developers, this means a greater emphasis on comprehensive responsiveness and continuous optimization. Embrace these changes to ensure your website not only meets Google’s standards but also delivers a superior experience to your users.

I am an Ad-Age, Emmy, Shorty, Telly, and Webby Award-Winning Social Media Strategist and Content Creator specializing in outdoor lifestyle, adventure, travel, and recreation brands. With 20 years of experience, I excel at connecting brands with their audiences by creating dynamic and engaging content. My work focuses on telling compelling stories that resonate with the outdoor lifestyle and foodie community, driving engagement, and building strong online communities for various brands and broadcast initiatives.