Here are some of the most useful filters provided by mod_pagespeed. Each one has a simple HTML example attached; click "before" to see the original file, and "after" to see what mod_pagespeed produces with that filter (and only that filter) enabled. The two versions should look exactly the same, but the "after" one will be (slightly) speedier. Use "view source" to see the mod_pagespeed difference!
add_instrumentation | Adds client-side latency instrumentation. | before | after |
extend_cache | Improves cacheability. | before | after |
collapse_whitespace | Removes unnecessary whitespace in HTML. | before | after |
combine_css | Combines multiple CSS files into one. | before | after |
combine_heads | Combines multiple <head> elements into one. | before | after |
move_css_to_head | Moves CSS into the <head> element. | before | after |
elide_attributes | Removes unnecessary attributes in HTML tags. | before | after |
inline_css | Inlines small external CSS files. | before | after |
inline_javascript | Inlines small external Javascript files. | before | after |
outline_css | Moves large inline <style> tags into external files for cacheability. | before | after |
outline_javascript | Moves large inline <script> tags into external files for cacheability. | before | after |
remove_quotes | Removes unnecessary quotes in HTML tags. | before | after |
remove_comments | Removes HTML comments. | before | after |
rewrite_css | Minifies CSS. | before | after |
rewrite_images | Rescales, and compresses images; inlines small ones. | before | after |
rewrite_javascript | Minifies Javascript. | before | after |