Recent statistics show that 47 percent of website visitors expect a site to load in less than 2 seconds. And if the site takes longer than 3 seconds to load, 40 percent of them will leave—and probably never return. Site load time and running speed isn’t just inconvenient—it can mean lost engagement and revenue as well as lower search rankings. A number of factors can affect the speed and responsiveness of your WordPress website, but a process called caching can speed things up by storing some data in static files on your WordPress hosting servers or a user’s browser.
Why Is Caching Important?
Whenever someone visits a website for the first time, a complex process begins. When the user requests a page, the WordPress core must send a query in its programming language PHP to the site’s database, which then returns the requested data back to the core. WordPress then combines all the collected data and generates an HTML page. That page is then returned to the website for display to the visitor. That’s a lot of steps and a lot of processing—and if it happens every time a page is requested, it can take considerably longer than a couple of seconds a user is willing to wait.
This is where caching comes into play. Caching is one of the best things you can do to improve your website loading time and functionality. WordPress caching is a way to eliminate some of those steps in subsequent requests for the same page so that the compiled page is stored in the web server or browser memory, ready to be delivered whenever needed without requiring every step in the original request. That makes pages have faster loading times and speeds up the functioning of the entire site.
How Does Caching Work?
A number of strategies are available to keep a WordPress site running fast, but caching is a free option that can be carried out by a number of WordPress plugins. When caching is activated on a WordPress website, the pages generated by an initial search request are stored as static HTML pages, so that they can be retrieved and displayed without the need for all the steps of an initial request. That means, though, that the cached static HTML page is like a snapshot of the page generated by the original request so that if the page is updated or edited, those changes won’t appear in the cached version of the files.
Caching for WordPress sites has two forms: browser caching (also called client caching) or server-side caching. Though both of these work by saving the static page generated from an original search request, they function somewhat differently. WordPress browser caching takes advantage of a user’s local computer to store cached files of static pages, which can then be delivered quickly upon any request to the website.
For larger sites with more complex databases, server-side caching is more efficient. Static versions of requests for pages and other kinds of data are cached directly in the site server’s hard disk or RAM. WordPress users of shared servers can typically cache data on the server hard disk, but those using VPS, or Virtual Private Server, hosting or dedicated hosting may also cache data in the server’s RAM.
Clearing the Cache: Keeping Data Fresh
Caching data captures a static version of any webpage, and because the PHP code that originally generated the page is “stripped out” for caching, that means a cached page can’t be updated without additional help from a WordPress plugin. But regular purging, or clearing, of your site’s cache, can eliminate those outdated pages and allow for new versions of edited pages or new posts. In that way, the most recently generated version of a page can be cached for immediate access by site visitors. When a page is not updated, the cached version can simply be downloaded again and again.
WordPress Caching Plugins
A Cache plugin can also manage data from outside sources. Pages generated by the site itself, such as pages or posts, are typically updated or created through the initiative of a site administrator. But many websites contain elements from external sources, such as Twitter feeds, Pinterest boards, or online shopping carts that are updated from outside the site. The caching process behaves differently for this kind of site content, and some caching plugins include advanced features to help keep this kind of data from affecting a site’s overall speed and caching performance.
Caching plugins can be installed from WordPress or a number of third-party designers from around the world. Once installed, caching plugins are managed from the site’s admin dashboard, with options for setting a variety of parameters such as intervals for clearing the cache and what types of content should be cached.
With only seconds to make that all-important first impression, WordPress caching plugins are key to keeping visitors engaged with your site with faster loading times. Caching sounds like a complicated feature that only skilled developers can use, but any user at any skill level can improve a website’s speed and performance with one of the many free and premium caching plugins designed for WordPress sites of all kinds.