The Power of WordPress Cache: A Guide to Lightning-Fast Websites
Posted October 1, 2024

In today’s digital age, a slow website can mean losing visitors, conversions, and, ultimately, business. That’s where caching comes in as a game-changer. But what exactly does a cache do, how many types are there, and just how much of an improvement can you expect?
In this post, we’ll explore the power of cache in WordPress and explain the role of tools like a cache warmer to keep your site operating at top speed. (A cheeky hint: this is how we are able to make our websites feel fast!)
What Does a Cache Do?
At its core, a cache temporarily stores copies of files or data so they can be quickly accessed instead of being generated anew each time they’re requested. When you have a WordPress site, this process saves time by loading pre-saved versions of pages or resources instead of generating them all over again for every visitor. Think of it as having a pre-packed suitcase rather than filling a new one every time you travel. For a WordPress site, caching speeds up load times, improves performance, and reduces the load on your server.
Types of Cache: From Browser to Server-Side
Note: This section gets a bit technical, but don’t worry! You’re about to learn something a bit techie that can help you understand why caching is so crucial for your website’s performance.
There are various types of cache, each serving a unique role in speeding up the web experience. Here are a few key levels of caching relevant to WordPress:
1. Browser Cache
The browser cache is managed by the end user’s browser (like Chrome or Firefox), which stores static resources (like images, CSS files, or JavaScript) on the user’s device. So, if someone visits your site multiple times, the browser loads these resources directly from the cache instead of re-downloading them. This cuts down on the number of requests to your server and speeds up load times for returning visitors.
2. Page Cache
This is often implemented by WordPress plugins like WP Rocket, W3 Total Cache, or others. Page caching stores fully-rendered HTML versions of pages, meaning when a visitor hits a page, it’s delivered from cache instead of going through the WordPress backend processes. For a dynamic platform like WordPress, page caching can make a huge difference, especially for content-heavy sites.
3. Object Cache
Object caching stores specific pieces of data that WordPress frequently uses, such as database query results. For instance, if your site makes the same database request multiple times, an object cache saves the result to reduce the need for repeated queries. This type of cache is beneficial for larger sites with complex database interactions and can be managed by plugins or through tools like Redis or Memcached. We use Redis for some of our bigger websites to ensure optimal performance.
4. Server Cache
Server-side caching, or full-page caching at the server level, is handled by your hosting provider. We use Nginx for our server caching, which adds another layer of efficiency by speeding up delivery before the browser even comes into play.
5. CDN (Content Delivery Network) Cache
CDNs like Cloudflare and Fastly store copies of your website on multiple servers worldwide. This makes your site’s assets (images, scripts, stylesheets) available from a location close to the visitor, cutting down on loading times, especially for users far from your main server. This also adds in a layer of security.
How Much Quicker Does Caching Make a Website?
To see caching’s real impact, let’s compare load times. Before adding caching, your WordPress site may take around 1,000ms (1 second) to load. With effective caching, we’ve seen load times drop to an astonishing 31ms. This massive improvement translates to more engaged visitors, fewer bounces, and a better user experience, not to mention an SEO boost, as search engines reward faster-loading sites with higher rankings.
What Does a Cache Warmer Do?
When a user first visits a page on your site, caching usually begins by creating and storing a copy for future visits. But what if we could preemptively create those cached copies? That’s where a cache warmer comes in. A cache warmer proactively loads all your pages and posts and creates cached versions before visitors even land on them. So, when someone does visit, they’re served an already-prepared, lightning-fast page.
Cache warming can be particularly useful after clearing your cache (such as during updates or plugin changes), ensuring there’s no delay in delivering that first request. By keeping your cache “warm,” this tool keeps your site continuously fast, even after updates.
Top Tip for Content Editors: Whenever you make changes to your content, remember to hit the “Purge Cache” button. This ensures that visitors always see the most updated content without delay.
Final Thoughts
Caching is one of the most effective tools for boosting WordPress performance, from browser and page cache to advanced server and object caching. And with cache warmers as a finishing touch, your WordPress site stays fast and ready, ensuring every visitor gets the best experience. So if you’re looking to make your WordPress site faster, caching isn’t just an option—it’s a necessity.

Mike Buckby
Mike, our skilled developer, brings a wealth of technical expertise to the team. His innovative solutions and dedication to quality help us deliver reliable, high-performing services to our clients.