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

Large JavaScript libraries can lead to poor performance. Prefer smaller, functionally equivalent libraries to reduce your bundle size

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

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

Consider using `<link rel=preload>` to prioritize fetching resources that are currently requested later in page load

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

Minifying CSS files can reduce network payload sizes

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 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/).

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

This is the largest contentful element painted within the viewport

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

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

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

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

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

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes

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

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

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

Remove unused JavaScript to reduce bytes consumed by network activity

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

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

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)

Redirects introduce additional delays before the page can be loaded

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

Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles

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

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

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

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

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

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

Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes

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

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

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

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)

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

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

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

Consider using `<link rel=preload>` to prioritize fetching resources that are currently requested later in page load

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

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

Minifying CSS files can reduce network payload sizes

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

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

Large JavaScript libraries can lead to poor performance. Prefer smaller, functionally equivalent libraries to reduce your bundle size

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

This is the largest contentful element painted within the viewport

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/).

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

Remove unused JavaScript to reduce bytes consumed by network activity

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

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

Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles

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

Redirects introduce additional delays before the page can be loaded