What is mod_expires?

mod_expires is an Apache Web server module installed on all of our Linux hosting accounts by default and supports all mod_expires functionality.

Mod_expires manipulates the Expires headers returned from the hosting server, letting you control how long a client's Web browser caches resources. You want to tune the duration of your caching to optimize performance while still considering how often you update the resource.

When the Expires header is already part of the response generated by the server, this module does not change or add an Expires or Cache-Control header—for example, when generated by a CGI script or proxied from an origin server.

For more information, see Enabling mod_expires with Your Hosting Account.