All these: https://developers.google.com/speed/docs/mod_pagespeed/filte... So image optimization, css and js minification, cache extension, css combining, image spriting, ...

But offloading things to CDN is actually one of the things it doesn't do. You might be thinking of the PageSpeed Service [1] which is a Google-hosted version.

[1] https://developers.google.com/speed/pagespeed/service

Wow. Thanks for bringing the service to my attention! Cut the load times on my sites by a ton.

You can see the complete list of filters (40+) here: https://developers.google.com/speed/docs/mod_pagespeed/confi...

Note that docs above are for mod_pagespeed (Apache), but all of the same filters are available in nginx port as well - it's the same C++ code under the hood. In a nutshell: HTML, CSS, JS, and image optimization (resizing, recompression, WebP, auto-spriting, etc...)

Configuring ngx_pagespeed: https://github.com/pagespeed/ngx_pagespeed#how-to-use

Thank you that's more helpful. Looks like a great tool

Jeremy, image optimization/compression, javascript minification/combination etc are some of the benefits we've tested and had tremendous success with.