Google Publishes Tutorial On Identifying INP Issues

Interaction to Next Paint (INP) is a metric that measures the time from when a user interacts with a page to when the browser is able to respond to that interaction. It has replaced First Input Delay (FID) as a Core Web Vital because it provides a more comprehensive understanding of the user's interactive experience on a web page. INP is now a key factor in how Google evaluates user experience.

To identify INP issues using Chrome DevTools, follow these steps:

1. Open Chrome DevTools: Right-click on the page and select 'Inspect' or use the shortcut Ctrl+Shift+I (Windows) or Cmd+Option+I (Mac).
2. Simulate a slower mobile device: Click the 'Device Toggle' icon, then select 'Mid-tier mobile' from the 'Network' tab.
3. Record user interactions: Go to the 'Performance' tab, click 'Record', interact with the page, and then click 'Stop'.
4. Analyze the performance: Expand the 'Interactions' track in the performance graph to see the response time.
5. Identify problematic code: In the 'Summary' pane, find and click the link to the page source to diagnose and fix the issue.

Common causes of poor Interaction to Next Paint (INP) scores include:

• Long-running JavaScript tasks: Break these into smaller, asynchronous tasks to avoid blocking the main thread.
• Excessive main thread activity: Optimize elements requiring significant processing, like scripts or animations.
• Overly complex DOM structures: Simplify HTML, merge CSS selectors, and reduce DOM tree depth.

Addressing these issues can significantly improve a site's INP score.

To meet the 'good' INP threshold, representing performance at the 75th percentile of page loads, follow these steps:

• Assess current INP performance using tools like PageSpeed Insights and Chrome User Experience Report.
• Analyze INP issues with Google's tutorial on Chrome DevTools.
• Implement fixes such as optimizing JavaScript and reducing main thread load.