What is caching?
A web cache (or HTTP cache) is the temporary storage (caching) of web documents, such as HTML pages and images, to reduce server lag. For example, when you return to a page you’ve recently looked at, the browser can get those files from the cache rather than the original server, saving you time and saving the network the burden of additional traffic.
Caching static files reduces several systems between an end user requesting your website and the delivery of the WordPress PHP files and thus, speeds up your WordPress site load time. Caching can be implemented on several levels and Website Pro has one level of caching implemented for you.
Website Pro built-in caching
Website Pro has a reverse proxy layer implemented with Nginx. Nginx is very fast and has an efficient caching mechanism. This can make viewing your changes awkward, but you can skip the cache by adding any URL parameters to the address: www.example.com/path/you/are/checking/?skip-cache
Currently Website Pro caches all content that matches the following criteria for 1 hour:
- Response was ok (200 status code)
- GET or HEAD requests (so not posting content)
- No URL parameters:
- So www.example.com/foo/bar matches
- But www.example.com/foo/bar?anything does not
- Request is not to the admin panel www.example.com/wp-admin/anything
- Request does not have a cookie that shows they
- Just posted the comment they’re looking at
- They are logged in
- They have wordpress_no_cache set
- They have wp-postpass set
WordPress Plugins can also implement some level of caching. This can cause some problems (see Divi File Caching for one example). CDN level caching is not natively supported in Website Pro at this time but it is in the long-range plan and Cloudflare can serve that purpose for now.