This is already built into the browser. Your browser sends "Accept-Encoding" listing what decoders it has (ex: "gzip, deflate, br"), and then the server may en

This is already built into the browser. Your browser sends "Accept-Encoding" listing what decoders it has (ex: "gzip, deflate, br"), and then the server may encode the body with any of them. If it does, it will send "Content-Encoding: gzip" or similar to indicate which it chose.