Report Summary

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    Best Practices

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Jacek Laskowski (@jaceklaskowski) on GitBook · GitBook (Legacy)

Page Load Speed

1.1 sec in total

First Response

144 ms

Resources Loaded

863 ms

Page Rendered

113 ms screenshot

About Website

Click here to check amazing Jacek Laskowski Git Book S content for China. Otherwise, check out these important facts you probably never knew about

Books written by Jacek Laskowski (@jaceklaskowski). Independent Consultant passionate about #ApacheSpark, #ApacheKafka, #Scala, #sbt (and #Mesos #DCOS) ~ @theASF member ~ @WarszawScaLa leader ~ Java C...


Key Findings

We analyzed page load time and found that the first response time was 144 ms and then it took 976 ms to load all DOM resources and completely render a web page. This is quite a good result, as only 15% of websites can load faster.

Performance Metrics performance score


Network Requests Diagram

144 ms


356 ms


69 ms


38 ms


54 ms

Our browser made a total of 19 requests to load all elements on the main page. We found that 5% of them (1 request) were addressed to the original, 37% (7 requests) were made to and 16% (3 requests) were made to The less responsive or slowest element that took the longest time to load (356 ms) relates to the external source

Page Optimization Overview & Recommendations

Page size can be reduced by 370.8 kB (64%)

Content Size

578.8 kB

After Optimization

208.0 kB

In fact, the total size of main page is 578.8 kB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 20% of websites need less resources to load. Javascripts take 231.5 kB which makes up the majority of the site volume.

HTML Optimization


Potential reduce by 24.5 kB

  • Original 32.0 kB
  • After minification 26.1 kB
  • After compression 7.5 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. This page needs HTML code to be minified as it can gain 5.8 kB, which is 18% of the original size. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 24.5 kB or 77% of the original size.

Image Optimization


Potential reduce by 44.7 kB

  • Original 134.0 kB
  • After minification 89.3 kB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. Obviously, Jacek Laskowski Git Book S needs image optimization as it can save up to 44.7 kB or 33% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization


Potential reduce by 148.3 kB

  • Original 231.5 kB
  • After minification 231.5 kB
  • After compression 83.2 kB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 148.3 kB or 64% of the original size.

CSS Optimization


Potential reduce by 153.3 kB

  • Original 181.4 kB
  • After minification 180.5 kB
  • After compression 28.1 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. needs all CSS files to be minified and compressed as it can save up to 153.3 kB or 85% of the original size.

Requests Breakdown

Number of requests can be reduced by 6 (35%)

Requests Now


After Optimization


The browser has sent 17 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Jacek Laskowski Git Book S. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 7 to 1 for JavaScripts and as a result speed up the page load time.

SEO Factors SEO score


Language and Encoding

  • Language Detected


  • Language Claimed


  • Encoding


Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise can be misinterpreted by Google and other search engines. Our service has detected that English is used on the page, and it matches the claimed language. Our system also found out that main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

Open Graph data is detected on the main page of Jacek Laskowski Git Book S. This is the best way to make the web page social media friendly. Here is how it looks like on Facebook: