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

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

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

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

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

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

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

Image formats like JPEG 2000, JPEG XR, and WebP often provide better compression than PNG or JPEG, which means faster downloads and less data consumption

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

Optimized images load faster and consume less cellular data

Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading

Consider instrumenting your app with the User Timing API to measure your app's real-world performance during key user experiences

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding [mixed content](https://developers.google.com/web/fundamentals/security/prevent-mixed-content/what-is-mixed-content), where some resources are loaded over HTTP despite the initial request being servedover HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs

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)

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

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/).

This is the largest contentful element painted within the viewport

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

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

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

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

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

Remove unused JavaScript to reduce bytes consumed by network activity

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

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

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

The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load

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

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

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

This is the largest contentful element painted within the viewport

Image formats like JPEG 2000, JPEG XR, and WebP often provide better compression than PNG or JPEG, which means faster downloads and less data consumption

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

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

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

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

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

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

Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading

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

Consider instrumenting your app with the User Timing API to measure your app's real-world performance during key user experiences

Remove unused JavaScript to reduce bytes consumed by network activity

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/).

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

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)

The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load

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

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

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

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

Optimized images load faster and consume less cellular data

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

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

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

All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding [mixed content](https://developers.google.com/web/fundamentals/security/prevent-mixed-content/what-is-mixed-content), where some resources are loaded over HTTP despite the initial request being servedover HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs

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

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