Gzip, Deflate, Brotli, and Zstd: Which Compression Algorithm Should You Use for Your Website?

When it comes to web performance optimization, reducing the size of the data sent from your server to the client is crucial. One of the easiest ways to achieve this is through compression. But with several algorithms to choose from — including Gzip, Deflate, Brotli, and Zstandard (Zstd) — how do you know which one is the best for your website?

In this article, we’ll break down each algorithm’s pros and cons and guide you on when to use each one to improve your site’s performance.

1. Gzip: The Old Reliable

Gzip is the most commonly used compression algorithm on the web today. Introduced in 1992, it has been the standard for HTTP compression for decades and remains widely supported by all browsers and servers.

Pros of Gzip:

• Wide Compatibility: Gzip is supported by virtually every browser and HTTP client, making it a reliable choice for almost any website.
• Fast Compression and Decompression: Gzip is fast in both compressing files and decompressing them on the client side, striking a good balance between performance and CPU usage.
• Moderate Compression: While Brotli and Zstd may offer better compression ratios, Gzip still provides decent file size reductions for most text-based content.

Cons of Gzip:

• Lower Compression Ratios: Gzip offers moderate compression, but it’s not as effective as newer algorithms like Brotli and Zstd, especially for CSS and JavaScript files.
• No Static Precompression: Unlike Brotli, Gzip doesn’t support precompressed static files, so compression is often done on the fly, consuming CPU resources.

Best Use Case:

Gzip is a great choice if you need broad compatibility across different browsers and platforms. It’s fast, efficient, and still widely used, especially on older systems or where quick compression is more important than squeezing out every last byte.

2. Deflate: The Legacy Option

Deflate is a compression algorithm that predates Gzip and is used in both HTTP’s Content-Encoding: deflate and ZIP files. In many ways, it’s similar to Gzip but with a few key differences.

Pros of Deflate:

• Widely Supported: Like Gzip, Deflate is supported by all major browsers and clients, ensuring cross-platform compatibility.
• Slightly Faster: Deflate is often a bit faster than Gzip when it comes to compression and decompression.

Cons of Deflate:

• Lower Security: There have been security vulnerabilities in the Deflate algorithm, making it less secure than Gzip or Brotli for certain use cases.
• Rarely Used: Although supported, Deflate is rarely used in modern web configurations, with Gzip or Brotli being more popular and offering better performance.

Best Use Case:

Deflate is largely considered outdated, and while it still works, there’s little reason to choose it over Gzip or Brotli unless you’re dealing with legacy systems that specifically require it.

3. Brotli: The Modern Champion

Brotli is a relatively new compression algorithm that was introduced by Google and is specifically designed for the web. It’s highly optimized for compressing text-heavy assets like HTML, CSS, and JavaScript, making it a strong contender for modern web applications.

Pros of Brotli:

• Best Compression Ratio: Brotli consistently offers better compression ratios than Gzip, especially at higher levels, making it ideal for reducing the size of web assets.
• Precompressed Static Files: Brotli supports precompression (using .br files), which allows servers to serve compressed files directly without having to compress them on the fly. This can significantly reduce CPU usage on the server.
• Optimized for HTTP/2 and HTTPS: Brotli is designed with modern web protocols in mind, particularly HTTP/2.

Cons of Brotli:

• Slower Compression: Brotli’s higher compression levels (7–11) are significantly slower than Gzip. However, the lower levels (1–5) are relatively fast and still offer better compression than Gzip.
• Limited Support on Older Browsers: Brotli is supported by all modern browsers (Chrome, Firefox, Safari, Edge), but older browsers like Internet Explorer do not support it.

Best Use Case:

Brotli is the ideal compression algorithm for modern websites that serve static assets over HTTPS and target modern browsers. It’s especially effective for compressing CSS and JavaScript files.

4. Zstandard (Zstd): The Speed Demon

Zstandard (Zstd) is a newer compression algorithm developed by Facebook, designed to provide both high compression ratios and fast speeds. It’s gaining popularity in high-performance applications but is not yet widely supported by browsers for HTTP compression.

Pros of Zstd:

• Extremely Fast: Zstd is incredibly fast, particularly at lower compression levels, making it ideal for scenarios where real-time compression is needed.
• Excellent Compression: Zstd can match or even exceed Brotli’s compression ratios, especially at higher compression levels, while still offering faster speeds.
• Efficient Decompression: Zstd’s decompression speed is faster than Brotli and Gzip, making it suitable for large-scale data transfers and systems that need high throughput.

Cons of Zstd:

• Limited Browser Support: Unlike Gzip and Brotli, Zstd is not yet supported by browsers for HTTP content encoding, so you can’t use it for client-side compression on typical websites.
• Still Maturing: Zstd is newer compared to Gzip and Brotli, meaning it hasn’t been as widely adopted or tested in web applications.

Best Use Case:

Zstd is a great choice for back-end systems or server-to-server communication where compression speed is critical. It’s also useful for data storage and file archiving, but not yet ready for use in traditional web serving due to limited browser support.

Comparison Summary

Final Thoughts: Which Compression Algorithm Should You Use?

• Use Gzip if you need wide compatibility across all browsers and platforms, or if your website serves users with older browsers.
• Use Brotli for modern web applications that can take advantage of HTTP/2 and HTTPS. It offers the best compression for text-based assets and can significantly reduce load times for CSS and JavaScript-heavy pages.
• Use Zstd in high-performance environments where fast compression and decompression speeds are crucial, but don’t rely on it for web compression until browser support improves.
• Use Deflate only if you’re maintaining legacy systems that specifically require it. For most modern use cases, Gzip or Brotli are better choices.

Ultimately, the choice of compression algorithm should align with your specific use case and target audience. For most websites today, Brotli is the clear winner for modern browsers, while Gzip remains a solid fallback for broad compatibility. If you’re running high-performance server systems, Zstd could be the next big thing — just not for client-facing web applications yet.

By choosing the right compression algorithm, you can greatly improve your site’s speed and deliver a better experience for your users.