2.0 1.1

Filter Selection

Choose which mod_pagespeed 1.1 filters to enable. RewriteLevel presets, CoreFilters defaults, EnableFilters, DisableFilters, and tuning thresholds.

mod_pagespeed 1.1 applies a set of filters to optimize your pages. You control which filters run through the RewriteLevel directive and per-filter enable/disable directives.

RewriteLevel

The RewriteLevel directive sets the baseline set of filters. Three levels are available:

CoreFilters (default)

A production-safe set of filters enabled by default. This level balances optimization impact with broad compatibility. Most deployments should start here and add or remove individual filters as needed.

   pagespeed 
 RewriteLevel CoreFilters; 
 
 

   ModPagespeedRewriteLevel CoreFilters 
 
 

   pagespeed RewriteLevel CoreFilters

PassThrough

No filters are enabled by default. Use this level when you want full control over exactly which filters run. You then enable individual filters with EnableFilters .

   pagespeed 
 RewriteLevel PassThrough; 
 
 

   ModPagespeedRewriteLevel PassThrough 
 
 

   pagespeed RewriteLevel PassThrough

OptimizeForBandwidth

Optimizes resources in place without altering HTML structure. Images are recompressed, CSS and JavaScript are minified, but no URLs are rewritten and no HTML is changed. This level is safe for environments where URL stability is critical.

   pagespeed 
 RewriteLevel OptimizeForBandwidth; 
 
 

   ModPagespeedRewriteLevel OptimizeForBandwidth 
 
 

   pagespeed RewriteLevel OptimizeForBandwidth

CoreFilters

When RewriteLevel is set to CoreFilters (the default), the following filters are enabled:

  • add_head — adds a <head> element if one is missing
  • combine_css — combines multiple CSS files into one
  • combine_javascript — combines multiple JavaScript files into one
  • convert_meta_tags — converts <meta http-equiv> tags to response headers
  • extend_cache — extends cache lifetime of resources by content-hashing URLs
  • fallback_rewrite_css_urls — rewrites URLs in CSS even when CSS parsing fails
  • flatten_css_imports — inlines @import rules in CSS
  • inline_css — inlines small CSS files into HTML
  • inline_import_to_link — converts CSS @import to <link> tags
  • inline_javascript — inlines small JavaScript files into HTML
  • rewrite_css — minifies CSS
  • rewrite_images — recompresses and resizes images
  • rewrite_javascript — minifies JavaScript
  • rewrite_style_attributes_with_url — rewrites URLs in style attributes

Enabling and disabling filters

EnableFilters

Adds filters on top of those already active from the RewriteLevel. Accepts a comma-separated list of filter names.

   pagespeed 
 EnableFilters collapse_whitespace,remove_comments; 
 
 

   ModPagespeedEnableFilters collapse_whitespace,remove_comments 
 
 

   pagespeed EnableFilters collapse_whitespace,remove_comments

DisableFilters

Removes filters from the active set. Use this to turn off specific CoreFilters you do not want.

   pagespeed 
 DisableFilters combine_css,combine_javascript; 
 
 

   ModPagespeedDisableFilters combine_css,combine_javascript 
 
 

   pagespeed DisableFilters combine_css,combine_javascript

ForbidFilters

Blocks filters from being enabled by any means, including query parameters and .htaccess overrides. Use this to lock down your configuration in multi-tenant or shared-hosting environments.

   pagespeed 
 ForbidFilters inline_javascript,inline_css; 
 
 

   ModPagespeedForbidFilters inline_javascript,inline_css 
 
 

   pagespeed ForbidFilters inline_javascript,inline_css

ForbidAllDisabledFilters

Automatically forbids every filter that is not currently enabled. This prevents users from enabling additional filters via query parameters or .htaccess .

   pagespeed 
 ForbidAllDisabledFilters 
 on 
 ; 
 
 

   ModPagespeedForbidAllDisabledFilters 
 on 
 
 

   pagespeed ForbidAllDisabledFilters on

Checking your filter configuration

Open the admin page at /pagespeed_admin/config in your browser to see the full list of active filters and their current settings. This page reflects the running configuration after all directives are applied.

Tuning parameters

Several directives control size thresholds and quality levels for filter behavior. The table below lists commonly adjusted parameters with their defaults.

Parameter Default Description
CssInlineMaxBytes
2048 Maximum size (bytes) of a CSS file to inline into HTML
JsInlineMaxBytes
2048 Maximum size (bytes) of a JavaScript file to inline into HTML
ImageInlineMaxBytes
3072 Maximum size (bytes) of an image to inline as a data URI
ImageRecompressionQuality
85 Quality level (0-100) for recompressed JPEG images
CssFlattenMaxBytes
102400 Maximum size (bytes) of CSS after flattening @import rules

Set these in your server configuration:

   pagespeed 
 CssInlineMaxBytes 
 4096 
 ; 
 
  pagespeed 
 ImageRecompressionQuality 
 75 
 ; 
 
 

   ModPagespeedCssInlineMaxBytes 
 4096 
 
  ModPagespeedImageRecompressionQuality 
 75 
 
 

   pagespeed CssInlineMaxBytes 4096 
 
  pagespeed ImageRecompressionQuality 75

URL preservation

By default, mod_pagespeed 1.1 rewrites resource URLs to include content hashes for cache extension. If you use a CDN or other infrastructure that requires stable, unchanged URLs, enable URL preservation for the affected resource types:

   pagespeed 
 EnableFilters image_preserve_urls; 
 
  pagespeed 
 EnableFilters css_preserve_urls; 
 
  pagespeed 
 EnableFilters js_preserve_urls; 
 
 

   ModPagespeedEnableFilters image_preserve_urls 
 
  ModPagespeedEnableFilters css_preserve_urls 
 
  ModPagespeedEnableFilters js_preserve_urls 
 
 

   pagespeed EnableFilters image_preserve_urls 
 
  pagespeed EnableFilters css_preserve_urls 
 
  pagespeed EnableFilters js_preserve_urls

With URL preservation enabled, mod_pagespeed still optimizes the resource content (recompression, minification) but serves it at the original URL. The optimized variant is loaded on the first request and served on subsequent requests via the in-place resource optimization flow.