Last month I mentioned Brotli for Nginx. On the client side, Firefox is aiming to add support for Brotli in version 44:
If all goes well in testing, Firefox 44 (ETA January 2016) will negotiate brotli as a content-encoding for https resources. The negotiation will be done in the usual way via the Accept-Encoding request header and the token “br”. Servers that wish to encode a response with brotli can do so by adding “br” to the Content-Encoding response header. Firefox won’t decode brotli outside of https – so make sure to use the HTTP content negotiation framework instead of doing user agent sniffing.
Chrome has Brotli support listed as “in development”. I didn’t see any indication of a current timeline for it showing up in a release version.