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

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

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

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 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

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)

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

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

This is the largest contentful element painted within the viewport

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

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

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

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

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

Descriptive link text helps search engines understand your content

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/).

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

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

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