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Caching site content with Jetpack Boost

Speed up website performance by storing frequently accessed content locally, reducing load times for visitors. 

To access the caching feature, ensure the Jetpack Boost plugin is installed and active. For installation instructions, visit our installation guide.

Enable page caching

To enable page caching:

  1. Go to Jetpack → Boost in WP Admin.
  2. Expand the “Page loading” section.
  3. Turn on the “Cache Site Pages” toggle.

Once enabled, Boost displays the “Clear cache” button, the Except panel, and the “Enable logging” toggle.

Verify that page caching works

You can verify that the cache is working by looking in wp-content/boost-cache/cache/ on your server for cached files. You can also open your site in a private or incognito browser (the plugin only caches page requests by logged-out visitors) and do the following:

  1. Open the Web Developer console and navigate to the Network tab.
  2. Clear the list, then reload the page.
  3. Click on the entry for your page and examine the Response Headers. You will find one called “X-Jetpack-Boost-Cache” with a value “hit” if it was served from the cache. If the page wasn’t cached, the value will be “miss”.

If a page is missing the “X-Jetpack-Boost-Cache” header, its URL is probably excluded from caching.

Check whether a page is cached

If your site behaves differently when you are logged in versus logged out, you may be seeing a cached HTML page served by an external caching layer (such as your hosting provider, a CDN, or another caching plugin).

To check this:

  1. Open the affected page in a private or incognito browser window.
  2. Add a query parameter (?nocache=1) to the URL. This will look like: https://yourjetpack.blog/?nocache=1
  3. Compare how the page loads with and without the parameter.

If the page loads correctly with the parameter but not without it, the site’s current code is correct and the issue is cache-related.

In this case, contact your hosting provider or review any other caching layers on your site and ask for a full cache purge.

Adding a query parameter does not fix the issue, it only bypasses the cache so you can confirm whether caching is the cause and continue troubleshooting.

Existing caching systems

Jetpack Boost detects when your site already uses another page caching system.

On supported hosting platforms, Boost can recognize page caching provided by your host. In this case, Boost shows Page Cache is running, and you don’t need to enable Jetpack Boost’s page cache or make changes to your hosting provider’s cache.

If Boost detects another caching plugin or caching system that prevents Jetpack Boost’s page cache from running, the “Cache Site Pages” toggle may be unavailable. To use Jetpack Boost’s page cache instead, disable the other caching solution first.

If you’re unsure which caching system your site uses, contact your hosting provider before making changes.

The technical side of caching

All page caches used by WordPress must use a special file in your wp-content directory called advanced-cache.php to drive their caching features. Jetpack Boost will show an “Existing Cache System Detected” message if we detect an advanced-cache.php file in your wp-content directory.

If you have access to the files in your WordPress installation, check this file to see if it contains information about what caching solution you currently have configured.

If you have an empty advanced-cache.php file installed, your hosting provider may have placed that file there to prevent you from using your own page caching solution. In such cases, your hosting provider likely has a cache built-in. We recommend that you contact your hosting provider for information.

Jetpack Boost provides several filters for developers looking to customize caching behavior. These include jetpack_boost_cache_bypass_patterns for changing bypass patterns, jetpack_boost_cache_request_cacheable to specify cacheable requests, and jetpack_boost_cache_accept_headers to modify caching based on content types.

Further details can be found in the Cache API documentation.

Exclude specific parts of the site from caching

You can exclude pages or posts that should always show the latest content.

To exclude URLs from the cache:

  1. Go to Jetpack → Boost in WP Admin.
  2. Expand the “Page loading” section.
  3. Turn on the “Cache Site Pages” toggle.
  4. Open the Except panel.
  5. Enter each URL path you want to exclude on a separate line.
  6. Select the Save button.

Enter URL paths without the full site address. For example, use checkout to exclude a single page. To exclude multiple URLs under the same path, use .*, such as gallery/.*.

Select the “See an example” link in Boost to view more examples.

Track caching events

If you run into trouble with page caching, enable logging to record cache events.

To enable cache logging:

  1. Go to Jetpack → Boost in WP Admin.
  2. Expand the “Page loading” section.
  3. Make sure the “Cache Site Pages” toggle is turned on.
  4. Turn on the “Enable logging” toggle.
  5. Select the “See logs” link to open the Cache debug log.

The Cache debug log records cache activity that can help with troubleshooting.

Select the “Copy to clipboard” button if you need to copy the log for troubleshooting or to share it with support.

Logging can add extra disk activity, so turn off the “Enable logging” toggle when you have finished troubleshooting.

Clear the cache

Jetpack Boost automatically clears cached content when posts are updated, published, or deleted, when comments change, and when you switch themes.

To clear the cache manually:

  1. Go to Jetpack → Boost in WP Admin.
  2. Expand the “Page loading” section.
  3. Make sure the “Cache Site Pages” toggle is turned on.
  4. Select the “Clear cache” button.

Manual cache clearing is useful if your site shows outdated content that has not refreshed automatically.

Adjust the cache duration

Content stays cached for 1 hour. This can be changed by adding a line to your site’s wp-config.php file.

define( 'JETPACK_BOOST_CACHE_DURATION', 3600 );

Where 3600 is the duration of the cache in seconds. You can adjust this value according to your needs to control the freshness of your cached content.

However, WordPress comes with a wide variety of plugins and settings, so it can miss some updates. If you notice that some content on your site appears to be out-of-date after making a change, you can clear your page cache at any time.  

Change cache parameters with filters

Jetpack Boost provides several WordPress filters that enable developers to customize how visitors are identified for serving cached content. These powerful features require some technical expertise to implement effectively. For detailed explanations of each filter and helpful example code to get you started, check out the Jetpack Boost Filters Documentation.

Troubleshooting caching issues

For troubleshooting Jetpack Boost caching issues, please refer to our Troubleshooting Guide for detailed solutions.

Get help

Need more help? Feel free to contact us! For free Jetpack Boost users, you can post a support request on the Jetpack Boost Plugin Support page. If you upgraded, you can contact support for more personalized assistance.