When enabling brotli, many resources are served with gzip instead of brotli compression when the Accept-Encoding of the client request allows both. How is it decided how a resource will be compressed? I assume Content compression | Brotli · Cloudflare Speed docs is the right article. Do I read it correct that if the origin already answers in gzip Cloudflare will not change it to brotli anymore?
Your understanding is correct. According to Cloudflare’s documentation on content compression, if the origin server responds with a resource already compressed in gzip, Cloudflare will serve it using gzip compression and will not change it to Brotli.