Brotli Vs Gzip Compression: Which Is Better For Website’s PageSpeed Optimization 

Brotli vs gzip compression You may wonder which data compression algorithm is more effective for website optimization. While compression plays a crucial role in a website’s PageSpeed performance, choosing a proper compression algorithm is essential for compatibility & to reach the best possible loading speed for your website.

Brotly vs gzip banner

To clear out all your confusion, here we will explain what are Gzip and brotli compression and the key differences between brotli vs Gzip. Also, we will figure out the advantage of using brotli compression over GZIP. and finally, explore how you can optimize your website by brotli compression algorithm with RabbitLoader.    

Understanding Compression And Its Importance On PageSpeed Performance

Before diving into the Gzip and brotli compression, let’s quickly discuss what compression is and its importance on your PageSpeed performance. Compression is one of the web optimization methods to reduce resource file size such as HTML, CSS, and JavaScript files, improving the loading time of your website.

 For modern web browsers, mostly three HTTP compression algorithms are used such as:

  • Gzip compression

  • Brotli Compression

  • Deflate Compression

When you use these compression algorithms, it can be possible to optimize all resource files on the server so that the files can be quickly retrieved from the server. It can significantly reduce the initial server loading time and boost your PageSpeed performance by improving the performance of core web vitals metrics. 

Note: GZIP and brotli compression are not applicable for image compression. To reduce the image file size, you need to convert them to next-gen format. If you want to know more details about it, please go through our previous blog on Next-Gen Formats.  

Here we will discuss the most popular two compression algorithms: Gzip compression and Brotli compression. 

The Importance Of Using A Compression Algorithm In Your Website  

The primary goal of any website owner should be to provide a seamless user experience and achieve a desirable conversion rate. Here PageSpeed plays a crucial role along with the other conversion rate optimization factors of a website. 

When considering PageSpeed optimization, the size of the resource files matters. If the file size of your HTML, CSS, and JavaScript is too large, it increases the loading time of your website. So, file size reduction is important to optimize the page loading time. 


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Several optimization techniques can be used to reduce the resource file size such as minifying resources , generating critical CSS, reducing unused CSS, and many more. Implementing a proper compression algorithm in the server is one of them. To reduce the file size more effectively, you need to enable Gzip compression algorithm, or also you can enable brotli compression. 

What Is Gzip Compression?

Gzip compression is the most traditional and common type of compression written by Jean-Loup Gailly and Mark Adler. Its first version (version 10) was published in 1993 while the meta version was released in 1992. 

Gzip compression can minimize the file size by replacing the long and repeated string with a single pointer, which can also reduce code redundancy. 

gzip compression

When a visitor opens your website, the server first checks if the user’s browser supports the Gzip file or not. If it supports the GZIP files, the server compresses the HTML, CSS, and JavaScript files before sending them to the browser. 

A compressed file is smaller than the original file, so the browser takes less time to load them. Consequently, the PageSpeed performance will automatically be improved of the website, enhancing the user experience.  

The Compression Mode In Gzip

Gzip is a combination of Huffman coding and the LZ77 algorithm. It offers nine levels of lossless file compression methods. Let’s cover the three methods commonly used on servers. 

  1. Compression Level 1: Fastest 

This compression method is applicable to small websites and can be used if you have limited server resources. This method is one of the fastest methods as it covers small file size reduction. 

  1. Compression Level 6: Default 

This compression method is used by many WordPress sides as it is able to maintain a proper balance of compression ratio and speed. This is the default compression level that is provided by most WordPress hosting provider. 

  1. Compression Level 9: Best

To apply this compression method, you need a proper server resource. In this case, you will get a smaller file size as it provides you with the highest compression rate. That’s why, a huge processing power is required in this compression method.   

The Advantage Of Gzip Compression 

Let’s see the advantages of the Gzip compression algorithm which include:

  1. Most modern web browsers and servers support GZIP compression.
  2. It has a huge library to help web developers implement and configure GZIP compression easily. 
  3. Gzip is a lossless compression. 

FAQ: What is Lossless Compression?

Lossless compression is one type of compression in which the entire data can be restored after decomposition. In simple words, in the case of lossless compression, after receiving compressed content from the server, when the user’s browser decompresses the file, it needs to be the same as the original.

The Limitation Of Gzip Compression

Gzip compression has some disadvantages which include:

  1. As you can see, most of the Gzip methods require an amount of server resources. This can affect CPU usage, harming your website’s performance. 
  1. Most WordPress hosting providers enable the default compression mode in Gzip. However, changing the compression mode can be a little challenging, especially for people with a non-technical background. 

What Is Brotli Compression?

Google always looks for a better solution. In 2013, two Google employees, Jyrki Alakuijala and Zoltan Szabadka, developed a modern compression algorithm called brotli compression. It normally provides a better compression ratio. 

Brotli compression

Brotli compression is used to compress the text-based content in the HTML, CSS, and JavaScript files. 

The Compression Mode In Brotli 

Brotli compression uses some advanced compression modes to achieve a better compression ratio without sacrificing speed. Let’s look at the compression level used in the brotli compression algorithm. 

  • Generic mode:

This generic mode is the default mode provided by WordPress hosting, and this compression level offers a good balance between speed and compression ratio. 

  • Text mode:

The text modei is specially designed for compression of the pain text. So, for text compression, you can implement the text mode of the brotli algorithm. 

  • Font mode:

As the name suggests, the font mode in the brotli compression level is designed for compressing the web fonts. 

Read More: Best Google Fonts

The Advantage Of Brotli Compression 

Let’s explore the advantage of brotli compression. 

  • Brotli compression method has a context model and dynamic library.
  • Brotli compression decompresses the file faster than GZIP compression which can lead to a quicker rendering process. 

The Limitation Of Brotli Compression

Despite its advantages, brotli compression also has some drawbacks. Before implementing brotli compression in your website for optimization purposes, you should know these drawbacks also. Let’s explore the advantages of brotli compression. 

  • Brotli needs server-side configuration so, for that you need to contact your hosting provider. 
  • Compared to Gzip, brotli has less browser support. 

The Difference Between Brotli Vs Gzip

While the main goal of brotli compression and Gzip compression is to reduce the file size, the is a difference between their functionality. Gzip was designed for file compression whereas brotli compression was specially developed for the web.  Here we will explore their functionality in detail. 

Key features Brotli Gzip 
Compression SizeBrotil provides a better compression ratio, especially for static data.When it comes to dynamic content, Gzip compresses the file more than brotli does. 
Compression Algorithm Brotli uses the LZ77 algorithm, Huffman coding, and a comprehensive static library. On the other hand, Gzip only uses the LZ77 algorithm, Huffman coding. 
Web Server Settings When you want to integrate brotli compression on your server side, you must make many changes to your server. Some hosting providers provide Gzip compression by default on your server.
Browser Supports Compared to Gzip, brotli is newer in the market. so, it has less browser support. Here, most of the browser supports Gzip compression. 

The Advantage Of Brotli Over Gzip

At this point, you already have a basic idea of which compression should you implement in your website to optimize the PageSpeed performance of your website. However, here we will talk through the advantages of using brotli compression over Gzip compression for your better understanding.  

Brotli compression is an amalgamation of a comprehensive static dictionary, advanced mechanism, and transformative mechanism that makes this algorithm more effective than the GZIP compression method.

Brotli’s comprehensive static dictionary makes the size of the file smaller by allowing to use of the keys instead of using the entire keywords.  Let’s see by doing so, how much brotli compression reduces each file size:

  • It reduces the HTML file size by approximately 20%
  • In the case of CSS stylesheets, with brotli compression, you can the file size by around 16%.
  • And finally for JavaScript files, after compressing the file with brotli compression, the file size is reduced by 15%. 

The another advantage of brotli compression over Gzip compression is its compression speed on the server side. Brotli is faster compression than GZIP. It takes less compression time. Not only compression but in some cases of decompression on the browser side, brotli decompression is approximately 64% faster than the Gzip decompression.  

Also, enabling brotli compression in your server will help you achieve a higher compression ratio compared to enabling Gzip compression. 

Brotli Compression With RabbitLoader 

While manually implementing the brotli compression algorithm on the server side needs the help of your hosting provider or a lot of effort, RabbitLoader makes this easier. RabbitLoader always strives to produce the best possible result for the users to enhance their PageSpeed performance of the website. 

Brotli compression with rabbitloader

As brotli compression is the superior form of the compression method, RabbitLoader does it for you when you are optimizing your website’s PageSpeed performance with RabbitLoader. Brotli compression is integrated into RabbitLoader, so, no other plugin is required for your WordPress website to implement the brotli compression algorithm.

Not only for WordPress websites but for other platforms such as Shopify, Laravel, and PHP, you can optimize the PageSpeed performance with RabbitLoader.


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