39 danielkorpai.com Last Updated: 3 years

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

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

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

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

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

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

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

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

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

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

Descriptive link text helps search engines understand your content

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

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

This is the largest contentful element painted within the viewport

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

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

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

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity

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

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

Serve images that are appropriately-sized to save cellular data and improve load time

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

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

Serve images that are appropriately-sized to save cellular data and improve load time

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

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

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)

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

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

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

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

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

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

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

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

Descriptive link text helps search engines understand your content

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

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

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

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

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

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

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

Largest Contentful Paint marks the time at which the largest 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

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity