Brotli Checker

Brotli Checker: Test If a Website Uses Brotli Compression

Brotli is a compression algorithm developed by Google that reduces the size of web content, making pages load faster. Many modern servers and CDNs support Brotli, but not all sites have it enabled. A Brotli checker tests whether a given URL is served with Brotli compression.

What Is Brotli?

Brotli is a lossless compression algorithm that combines a modern LZ77 variant with Huffman coding and a built-in dictionary. It is particularly effective for text-based content like HTML, CSS, and JavaScript. Compared to gzip, Brotli often achieves better compression ratios, especially at higher quality settings.

Why Check for Brotli

• Performance: Smaller files load faster, which improves user experience and can positively affect search rankings.
• Bandwidth: Compression reduces bandwidth usage, which can lower hosting costs.
• Compatibility: Most modern browsers support Brotli, but some older clients do not.
• Optimization: If a site is not using Brotli, enabling it can be a quick performance win.

How Brotli Checking Works

The checker sends a request to the URL with an Accept-Encoding header that includes br (the identifier for Brotli). It then examines the Content-Encoding header in the response. If it contains br, Brotli is enabled. If it contains gzip or nothing, Brotli is not being used for that response.

Things to Keep in Mind

Brotli requires HTTPS in most browsers, although it can technically be used over HTTP. The server must be configured to compress responses with Brotli, and the client must support it. Some CDNs automatically enable Brotli, while others require manual configuration. Also, not all content types are compressed — images and videos are usually already compressed and may not benefit from Brotli.

Practical Scenarios

If you are optimizing a website, checking for Brotli is a good way to identify a potential improvement. If it is not enabled, you can configure your server or CDN to use it. If you are comparing performance between sites, Brotli support is one factor to consider. In development, testing Brotli ensures that your content is delivered efficiently.

Limitations

A Brotli checker only tells you whether the URL responded with Brotli compression for a specific request. It does not measure the actual compression ratio or performance impact. Different requests may receive different responses depending on the content type, the client, and the server configuration. Use it as a starting point for further investigation.

Summary

A Brotli checker tests whether a website uses Brotli compression. It is a quick way to assess one aspect of a site's performance configuration. Understanding the benefits of Brotli helps you decide whether to enable it on your own servers.