In this article, we’ll introduce you to the basics of caching, how you can test your site to identify speed issues, and help you decide if caching can help minimize those problems.

‘Caching’ is a term you’ve almost certainly come across multiple times when creating a WordPress website. However, what does it actually mean, how does it work, and why should you care? In short, caching can be a critical tool for improving the performance and speed of your website.

While the concept itself is simple, it can be difficult to know where to begin if you want to implement it on a WordPress site. Fortunately, there are many WordPress caching plugins available to help you get started.

What Caching Is (And Why It’s Important)

In short, caching refers to data that’s saved and stored temporarily. The next time the user accesses the site, they don’t have to load every single file from your site; it will be saved in the cache, which will significantly speed things up.

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On the other hand, if a site is not cached the browser will need to load its entire contents — including all text and media files — every time the site is loaded. This will happen even if nothing has changed since the last visit.

It’s also worth noting that these caches can be located in more than one place:

  • Client-side caching — This is also known as ‘browser caching’ and refers to a process that most internet browsers today perform automatically. The browser will save static data — such as CSS, JavaScripts, and images — on the user’s local hard drive and re-use them the next time the site is accessed from the same device.
  • Server-side caching — This type of caching occurs on the server-side, and is what you primarily need to think about when optimizing a WordPress site. This is especially true if you run a traffic-heavy site or even a low-traffic site on shared hosting. This can also be a lot more complex in nature, which depends on your site’s structure and requirements.

More involved systems also use multiple caching servers at once, also known as ‘reverse proxy servers.’ These work as a middleman between the visitor and the site by sitting ‘in front’ of the server where the WordPress site is hosted.

We’ll be taking a closer look at reverse proxy servers later on in this article, but for now, we’re going to check out how to assess your own site’s needs.

How to Determine Whether Your Site Has an Issue With Loading Speeds

In short, it’s crucial that your site loads quickly. Finding out how your site loads in other countries is also important, especially if you have a global audience. Fortunately, there are many tools available to help test your site’s performance.

This will give you a better idea of how quickly your site loads, and also how the site performs to users depending on their geographical location. Let’s look at two of our favorites.

1. Pingdom Tools

Pingdom Website Speed Test
Pingdom Website Speed Test

Pingdom Tools is a very simple and useful tool that will test your site based on several different metrics. Most importantly, it will provide your site loading speed, but it also returns the page size, the number of requests, and gives it an overall performance grade to assess your site at a glance.

Perhaps the best thing about this tool is how quick and easy it is to use. You simply enter the URL for the site you want to test, use the drop-down menu to select the location of the ‘user,’ then click Start Test. If the service is particularly busy, you might be placed in a short queue, but it generally takes less than a minute for your test to complete.

How to Implement Caching on Your WordPress Website

Once it has done so, you’ll see its results on the page. You can scroll further down to see more advanced information about specific parts of your site, and there’s a handy ‘legend’ to help you decipher what you’re reading.

In our opinion, it’s always a good idea to run the same test a few times, because no test will ever return the same results. You should also try out a few different locations to make sure you get a comprehensive view of how your site performs globally.

2. LoadImpact

How to Implement Caching on Your WordPress Website

LoadImpact is a more advanced alternative than Pingdom Tools, but it also offers you more incisive data. Essentially, this solution is concerned with how multiple visitors affect your loading speeds. It loads 25 virtual users over a five-minute period and plots the results on a graph in real time.

How to Implement Caching on Your WordPress Website

To use LoadImpact, enter a URL and click Run Free Test. The server loading will begin straight away and will return the resulting data in real time. You’re free to open new browser tabs while the test is running, but navigating away from the page will mean you’ll have to restart the test.

Beneath the main graph, you’ll find some additional information, such as bandwidth usage, the loading time for different types of content, and more. As with Pingdom Tools, we recommend running the test a few times to get the most accurate data.

Deciding Whether Caching Is the Right Solution For You

So far we’ve talked a lot about caching and the need to keep your site fast and well-optimized. However, is caching strictly necessary to accomplish this? Implementing it on your site will not just improve User Experience (UX), it can have a tangible positive effect on your bottom line as well.

Having a slow loading website is no small problem, as it can be catastrophic for your bounce rate. It’s no secret that people are far more likely to leave a site if it doesn’t load quickly and reliably. In fact, 47% of internet users expect sites to load in 2 seconds or less, and a single second delay can lead to as much as a 7% reduction in conversions.

The speed at which a site loads can also affect search engine rankings, so if your site loads quickly it’s more likely to appear higher in search results. When every second counts, it’s important to use every tool available to you, and caching is a great and simple way of ensuring your site runs rapidly.

However, you should be aware that while caching is a great tool for optimizing your site, it can cause issues. The most important of these is the risk of displaying old, outdated content on your site — most pertinent for constantly updated websites.

Obviously, making the loading times shorter is pointless if the site itself doesn’t show the correct content to visitors, so you need to make sure that the cache is cleared (or ‘purged’) appropriately.

If your site also contains a lot of dynamically updated content, such as a storefront with a shopping cart or a live Twitter feed, be aware that caching can interfere with these. In these cases, it may be best to consider which parts of your site to cache beforehand to avoid causing problems down the line.

While we recommend you implement some form of caching solution on your website, you shouldn’t stop there. As we pointed out earlier, optimizing your site’s speed should be a high priority and caching is only one tool at your disposal. There are plenty of other things you can — and should — do to improve your site’s speed. We recommend considering the following:

  • Reducing the size of your images. Uncompressed images are a common reason behind slow loading times. It’s therefore important to optimize your site’s media. This can either be done using an image editor or WordPress plugin.
  • Optimizing your database. You should routinely check that your databases are in good health. If this sounds too technical, don’t worry. Using a plugin such as WP-DBManager lets you check, repair, and backup your databases easily.
  • Checking your site’s speed regularly. We already talked about how to test your site using online tools, but it bears repeating. Over time, the performance of your site will change, depending on its contents and structure, so it’s important you keep up to date with testing to stay ahead of problems.