Microsoft Introduces Brotli compression in Microsoft Edge

Microsoft has announced that Edge browser now supports Brotli as an HTTP content-encoding method. This is feature is now available for Insider with Windows 10 build 14986. The final version will be released with the Windows 10 Creators Update early next year. With this release, Brotli will be broadly interoperable across browsers, with support in the latest versions of Microsoft Edge, Firefox, and Chrome.

Brotli is a compression format defined in RFC 7932, previously available as part of the WOFF2 font format. When used as an HTTP content-encoding method, Brotli achieves up to 20% better compression ratios with similar compression and decompression speeds (PDF). This ultimately results in substantially reduced page weight for users, improving load times without substantially impacting client-side CPU costs. As compared to existing algorithms, like Deflate, decompression with Brotli is much less expensive without sacrificing compression ratios.

Currently, Microsoft Edge in build 14986 supports Brotli on HTTPS and HTTP connections. In a future preview release, the company will update Brotli to support only HTTPS connections. Right now, there is a known issue which results in the F12 Developer Tools incorrectly not showing the accept encoding response header.