PageSpeed Filters

PageSpeed improves web page latency by changing the resources on that web page to implement web performance best practices. Each sort of change that PageSpeed makes is embodied in a filter. The filters are run in a pre-defined order, but can be enabled and disabled in the server configuration file.

Some filters simply alter HTML content, such as removing excess whitespace, attributes, or attribute values that will be ignored.

Other filters change references to CSS, JavaScript, or images to point to more optimized versions, because they:

Categories of filters

Filters are of many categories that fit under performance best practices. The current set of filters fits in these categories as follows:

Optimize Caching

Minimize Round Trip Times

Minimize Request Overhead

Minimize Payload Size

Optimize Browser Rendering


In some cases, a filter such as 'Optimize Images' helps both minimize request overhead and optimize browser rendering.