* PageSpeed Insights: tells you how to make your website faster and gives you a score.
* PageSpeed Modules (mod_pagespeed/ngx_pagespeed): open source web server plugins that rewrite your site to load faster.
* PageSpeed Service: Google-hosted proxy version of the PageSpeed Modules.
We're only deprecating PageSpeed Service.
(I'm the TL for the open source modules.)
If you are using PageSpeed integration on Google App
Engine, it will continue to function until 1st
December 2015, after which PageSpeed optimizations
will no-longer be applied to your app. No action is
required on the part of App Engine users; after this
date apps will continue to operate, except without
the benefit of the PageSpeed optimizations.