How does Batcache page caching work?

Batcache WordPress page caching is one of the three levels of caching Pressable uses to ensure your site loads quickly and efficiently.

Batcache stores your website’s entire HTML pages in memory using Memcached. It primarily focuses on caching dynamic page content and does not handle static assets such as fonts, images, CSS, or JavaScript files.

Batcache does not cache fonts or other static assets. Its caching mechanism is designed to store complete HTML responses, excluding static resources. Static assets are typically served through a Content Delivery Network (CDN) and Edge Cache.

To achieve page caching, we use a drop-in plugin called Batcache, which is “symlinked” as advanced-cache.php in the wp-content folder on every Pressable site.

Batcache stores and serves rendered pages. In a nutshell, when your page receives two visits within a period of two minutes, a cached version of the page is stored on the second visit for five minutes. Future visitors will receive the cached version for five minutes, after which a fresh render of the site will be used.

To verify that your page is indeed being cached by Batcache

Load the source code of your page. For example: view-source:https://pressable.com/. You should see an HTML comment like this at the very bottom of the page:

How to Check Cache Headers Using Browser Developer Tools

• Right-click on the page and select Inspect Element
• Click on the Network tab
• Reload the page to populate the network activity
• Click on the first entry in the list (usually the page URL)
• In the right panel, select the Headers tab to view the HTTP request and response headers. More info here

If Batcache is active you should see – x-nananana
Batcache-Hit under the Response Header.

How to Check Cache Headers From Command Line

• Open terminal or command line tool
• Run curl -I https://your-site.com

• -I tells curl to fetch only the HTTP headers. Look for cache-related headers such as:
  • Cache-Control
  • x-nananana Batcache-Hit
  • Last-Modified

Batcache should always be functional on a site. However, there are cases where caching may not work. For example, if your site hasn’t been loaded twice in the last two minutes, there will not be a cached version of the page stored. Additionally, if pages on your site are loading cookies with the prefix wp or wordpress, Batcache exempts these pages from caching. It is also possible that your site is using custom caching rules that exempt certain pages from caching, learn how Batcache works on Pressable.

You can extend batcache for your site as well. This will help to speed it up if traffic is low: Extend Batcache at Pressable