Compression is a process that reduces the size of files transferred between a web server and a visitor’s browser. Smaller files require less bandwidth and can be delivered more quickly, which helps improve website loading times.
In web hosting environments, the most commonly used compression algorithms are Gzip and Brotli.
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How compression works
When a browser requests a webpage, the server can compress the response before sending it.
The browser then automatically decompresses the content and displays the website normally.
Compression is typically applied to text-based files such as:
- HTML
- CSS
- JavaScript
- XML
- JSON
Files that are already compressed, such as JPEG images, MP4 videos, or ZIP archives, usually do not benefit significantly from additional compression.
What is Gzip?
Gzip is one of the most widely used web compression methods. It has been a standard part of web servers and browsers for many years.
Its main advantages are:
- broad compatibility
- low resource requirements
- reliable performance
- support across virtually all modern browsers
Because of its widespread adoption, Gzip remains a common choice for website compression.
What is Brotli?
Brotli is a newer compression algorithm developed to improve compression efficiency for web content.
Compared to Gzip, Brotli can often reduce file sizes further, especially for HTML, CSS, and JavaScript files.
Its advantages include:
- higher compression ratios
- reduced bandwidth usage
- potentially faster page delivery
- support in modern browsers
Brotli is commonly used on performance-focused websites and content delivery networks (CDNs).
Brotli vs Gzip
Brotli ≠ Gzip
| Feature | Brotli | Gzip |
|---|---|---|
| Compression efficiency | Higher | Lower |
| File size reduction | Better in many cases | Good |
| Browser support | Modern browsers | Nearly universal |
| Processing requirements | Higher during compression | Lower |
In most scenarios, Brotli produces smaller compressed files, while Gzip offers broader compatibility and lower processing overhead.
What does this mean for website visitors?
When compression is enabled:
- pages require less data to be transferred
- websites can load faster
- bandwidth consumption is reduced
- server responses become more efficient
The exact performance improvement depends on the website structure, file types, and visitor connection speed.
Practical implications
Compression works automatically once enabled on the server or through website optimization tools.
Visitors do not need to configure anything in their browsers. If the browser supports the selected compression method, decompression happens automatically.
Many modern hosting environments and web servers support both Brotli and Gzip, selecting the most appropriate method based on browser capabilities.
Summary
Compression reduces the size of website files before they are sent to visitors. Gzip is the long-established web compression standard, while Brotli is a newer algorithm that often achieves better compression ratios. Both help improve website performance by reducing the amount of data transferred between the server and the browser.