Brotli Compression

Brotli is a lossless compression method that web servers and delivery networks can use for eligible resources such as HTML, CSS, and JavaScript. The browser can advertise support with an Accept-Encoding request header, and an appropriately configured server can return a Brotli-encoded response identified by Content-Encoding: br. Compression reduces data transferred over the network; the browser decodes it before using the resource.

Imagine a local services website with a large stylesheet and several scripts. Enabling the right compression at the hosting or content delivery layer may reduce transfer size, especially for text-based files. However, image formats such as JPEG and WebP are commonly compressed already, so applying another general-purpose encoding may bring little benefit. Measure actual response headers and network transfer sizes rather than assuming a speed improvement from an optimization toggle.

Compression alone cannot resolve render-blocking JavaScript, slow server processing, missing caching rules, or inefficient images. Cached compressed and uncompressed variants also need correct HTTP negotiation behavior. A test on one network connection is not a universal performance guarantee. This entry focuses on the specific Brotli format and its HTTP use, not general image optimization, gzip compression, or the overall page-weight metric.