Largest Contentful Paint marks the time at which the largest text or image is painted

Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this

To set budgets for the quantity and size of page resources, add a budget.json file

First CPU Idle marks the first time at which the page's main thread is quiet enough to handle input. [Learn more](https://web.dev/first-cpu-idle/).

Cumulative Layout Shift measures the movement of visible elements within the viewport

Keep the server response time for the main document short because all other requests depend on it

Large network payloads cost users real money and are highly correlated with long load times

A long cache lifetime can speed up repeat visits to your page

Network round trip times (RTT) have a large impact on performance. If the RTT to an origin is high, it's an indication that servers closer to the user could improve performance

First Contentful Paint marks the time at which the first text or image is painted

Remove unused JavaScript to reduce bytes consumed by network activity

Time to interactive is the amount of time it takes for the page to become fully interactive

First Meaningful Paint measures when the primary content of a page is visible

A large DOM will increase memory usage, cause longer [style calculations](https://developers.google.com/web/fundamentals/performance/rendering/reduce-the-scope-and-complexity-of-style-calculations), and produce costly [layout reflows](https://developers.google.com/speed/articles/reflow)

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay

Estimated Input Latency is an estimate of how long your app takes to respond to user input, in milliseconds, during the busiest 5s window of page load. If your latency is higher than 50 ms, users may perceive your app as laggy

These DOM elements contribute most to the CLS of the page.

Server latencies can impact web performance. If the server latency of an origin is high, it's an indication the server is overloaded or has poor backend performance

Remove dead rules from stylesheets and defer the loading of CSS not used for above-the-fold content to reduce unnecessary bytes consumed by network activity

The maximum potential First Input Delay that your users could experience is the duration of the longest task

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this

This is the largest contentful element painted within the viewport

Speed Index shows how quickly the contents of a page are visibly populated

Some third-party scripts may contain known security vulnerabilities that are easily identified and exploited by attackers

Font sizes less than 12px are too small to be legible and require mobile visitors to “pinch to zoom” in order to read. Strive to have >60% of page text ≥12px

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this

First Contentful Paint marks the time at which the first text or image is painted

A long cache lifetime can speed up repeat visits to your page

Interactive elements like buttons and links should be large enough (48x48px), and have enough space around them, to be easy enough to tap without overlapping onto other elements

A large DOM will increase memory usage, cause longer [style calculations](https://developers.google.com/web/fundamentals/performance/rendering/reduce-the-scope-and-complexity-of-style-calculations), and produce costly [layout reflows](https://developers.google.com/speed/articles/reflow)

Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay

Network round trip times (RTT) have a large impact on performance. If the RTT to an origin is high, it's an indication that servers closer to the user could improve performance

Some third-party scripts may contain known security vulnerabilities that are easily identified and exploited by attackers

Speed Index shows how quickly the contents of a page are visibly populated

Keep the server response time for the main document short because all other requests depend on it

To set budgets for the quantity and size of page resources, add a budget.json file

Server latencies can impact web performance. If the server latency of an origin is high, it's an indication the server is overloaded or has poor backend performance

Largest Contentful Paint marks the time at which the largest text or image is painted

First CPU Idle marks the first time at which the page's main thread is quiet enough to handle input. [Learn more](https://web.dev/first-cpu-idle/).

Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds

Time to interactive is the amount of time it takes for the page to become fully interactive

Remove dead rules from stylesheets and defer the loading of CSS not used for above-the-fold content to reduce unnecessary bytes consumed by network activity

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this

This is the largest contentful element painted within the viewport

First Meaningful Paint measures when the primary content of a page is visible

Remove unused JavaScript to reduce bytes consumed by network activity

Estimated Input Latency is an estimate of how long your app takes to respond to user input, in milliseconds, during the busiest 5s window of page load. If your latency is higher than 50 ms, users may perceive your app as laggy

Large network payloads cost users real money and are highly correlated with long load times

The maximum potential First Input Delay that your users could experience is the duration of the longest task

First Contentful Paint 3G marks the time at which the first text or image is painted while on a 3G network