Optimize WordPress for Page Speed YSlow and Zoompf

Here are some optimization techniques to optimize your WordPress site for Google Page Speed 1.10.2, Yahoo YSlow 2.1.0, and Zoompf.

I installed a completely new WordPress 3.1 site with no plugins and using the default Twenty Ten theme.

Here are the relevant scores on a fresh install:

1. Edit your .htaccess file by adding the following:

   <IfModule mod_headers.c>
   Header unset ETag
   FileETag None
   </IfModule>
   
   <IfModule mod_expires.c>
   ExpiresActive on
   ExpiresByType image/jpeg "access plus 6 months"
   ExpiresByType image/png "access plus 6 months"
   ExpiresByType image/gif "access plus 6 months"
   ExpiresByType text/css "access plus 6 months"
   ExpiresByType application/javascript "access plus 6 months"
   ExpiresByType application/x-javascript "access plus 6 months"
   </IfModule>
   
   <IfModule mod_deflate.c>
   AddOutputFilterByType DEFLATE text/html text/css text/plain text/xml application/javascript application/x-javascript
   </IfModule>

2. In your /wp-content/themes/twentyten/header.php remove the following line: (this removes the charset from your page because it’s not needed if the web server is using the HTTP Content-Type header to define the character set)

   <meta charset="<?php bloginfo( 'charset' ); ?>" />

3. In your /wp-content/themes/twentyten/functions.php add the following: (this removes the ability to use remote editing)

   function remheadlink() {
   remove_action('wp_head', 'rsd_link');
   remove_action('wp_head', 'wlwmanifest_link');
   }
   add_action('init', 'remheadlink');

4. Optimize the /wp-content/themes/twentyten/images/wordpress.png using a tool such as ImageOptim. This will reduce the size of the image from 849 bytes to 661 bytes without losing any quality.
5. Optimize the /wp-content/themes/twentyten/images/headers/path.jpg by saving it with a jpeg quality setting of 75% using your favorite image editing tool and then using a tool like ImageOptim. This will reduce the size of the image from 51,727 bytes to 42,154 bytes without losing too much quality.
6. Minify the /wp-content/themes/twentyten/styles.css using the YUI Compressor tool.

Here are the new scores after optimization:

Here are the remaining issues:

Page Speed:

• Use efficient CSS selectors
• Minify HTML

YSlow:

• Use a Content Delivery Network (CDN)

Zoompf:

• RSS Feed Without Blackout Period (skipDays)
• RSS Feed Without Blackout Period (skipHours)
• RSS Feed Without Caching (TTL tag)
• Dynamic HTML Not Minified
• Potentially Cacheable Text Response (iPhone)
• Uncacheable Response (iPhone)

I hope you learned some simple steps on how to optimize your WordPress site.