Performance Insights provide actionable insights on your website's performance and are available in both the DevTools Performance panel and Lighthouse.
DevTools Performance Panel Lighthouse Performance audits
Identifies complex CSS selectors that take a long time for the browser to match with elements on the page.
Identifies reasons why the HTML document request takes longer than expected.
Pinpoints identical JavaScript modules or code being loaded multiple times within a single page.
Evaluates the `font-display` CSS property to ensure text remains visible while custom fonts are loading.
Identifies when JavaScript forces the browser to recalculate the layout of the page, potentially causing performance issues.
Suggests ways to optimize image loading, such as by using modern formats like AVIF or WebP and ensuring correct sizing.
Shows the INP subparts to help identify optimization opportunities to improve INP.
Points out the specific DOM elements responsible for unexpected movement on the page, which contributes to Cumulative Layout Shift.
Shows the LCP subparts to help identify optimization opportunities to improve LCP.
Identifies reasons why the LCP image request takes longer than expected.
Flags outdated JavaScript code that may be slower and unnecessary for most modern browsers.
Checks for newer network protocols like HTTP/2 or HTTP/3 to improve request and response multiplexing and speed.
Identifies key dependecy chains that are blocking the initial rendering of the page.
Identified when there are a large number of HTML elements on a page which can affect rendering performance.
Checks that the page's viewport is configured correctly to ensure it does not cause a 300 millisecond tap delay on mobile devices.
Identifies resources that block the inital rendering of the page delaying LCP.
Lists third-party resources that are loaded on the page.
Identifies suboptimal caching policies resulting in potentially unnecessary downloads on repeat visits to the page.