Кеширането е способ за намаляне на натоварването върху сървъра.
Това може да се дефинира с апаче като се използва mod_expire
<IfModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType image/x-icon "access plus 2692000 seconds"
ExpiresByType image/jpeg "access plus 2692000 seconds"
ExpiresByType image/png "access plus 2692000 seconds"
ExpiresByType image/gif "access plus 2692000 seconds"
ExpiresByType application/x-shockwave-flash "access plus 2692000 seconds"
ExpiresByType text/css "access plus 2692000 seconds"
ExpiresByType text/javascript "access plus 2692000 seconds"
ExpiresByType application/x-javascript "access plus 2692000 seconds"
ExpiresByType text/html "access plus 600 seconds"
ExpiresByType application/xhtml+xml "access plus 600 seconds"
</IfModule>
<IfModule mod_headers.c>
<FilesMatch "\\.(ico|jpe?g|png|gif|swf|css|js)$">
Header set Cache-Control "max-age=2692000, public"
</FilesMatch>
<FilesMatch "\\.(x?html?|php)$">
Header set Cache-Control "max-age=600, private, must-revalidate"
</FilesMatch>
Header unset ETag
Header unset Last-Modified
</IfModule>