The website optimizer can make several optimizations and suggestions for both PHP and HTML files. It's very easy to use, completely free and helps save bandwidth, processor speed and reduce load times.

I wrote the entire application myself including the complex algorithm which can optimize HTML inside of PHP. I am also completely confident in the security of this application which allows users to upload potentially executable files and then serve it back to them.

Nginx

nginx is a lightweight, high-performance Web server/reverse proxy and e-mail (IMAP/POP3) proxy, licensed under a BSD-like license. It runs on UNIX, GNU/Linux, BSD variants, Mac OS X, Solaris, and Microsoft Windows. Nginx powers 20-26% of all websites commonly surveyed, including most of the high-traffic sites.