How to Test WP Super Cache

Test within WP Super Cache

This plugin has a cache tester built into the settings page. Follow these steps to test it:

1. Go to Settings -> WP Super Cache
2. Look for the “Cache Tester” form on the easy settings page.
3. Click “Test Cache” and the plugin will request the front page of the site twice, comparing a timestamp on each to make sure they match.

Test WP Super Cache manually

Sometimes the tester fails, usually if the server is not configured correctly or there are strict security rules blocking those requests, and it can’t send a request to itself.

In those cases you need to test the caching manually:

1. In the Debug settings page of the plugin make sure that “Cache Status Message” is enabled.
2. Open a private/incognito browser window and load your website.
3. View the source of the page and examine the timestamp at the end of the page. It should look like:

<!-- Dynamic Page Served (once) in 0.829 seconds -->
<!-- Cached page generated by WP-Super-Cache on 2009-01-12 16:11:54 -->
<!-- Compression = gzip -->

4. Force reload the page (hold shift and click on reload) and view the source again.
5. Confirm that the timestamp matches what you saw when you loaded the page for the first time.
6. If timestamps do not match, then enable the debugging in the plugin. The debug log should explain why a cached page wasn’t saved or served.

Check HTTP headers

You can also check if WP Super Cache is working by looking at the HTTP headers. You’ll see that PHP-cached pages will have the header “WP-Super-Cache: Served supercache file from PHP”. WPCache cached files will have the header, “WP-Super-Cache: Served WPCache cache file”. You should also look for your cache directory in wp-content/cache/supercache/hostname/ for static cache files.

If the plugin rules are missing from your .htaccess file, the plugin will attempt to serve the super cached page if it’s found. In this case, you’ll see that the header will be “WP-Super-Cache: Served supercache file from PHP”. The pagespeed module for Apache may cause problems when testing. Disable it if you notice any problems running the cache tester.