When it comes to websites, the word cache gets thrown around quite a lot. But what actually is a cache? And why do people keep talking about it when it comes to speeding up your site?
At its core, a cache is just a way of storing information so it’s quicker to load the next time you need it.
In the context of websites, there are two main types of cache you’re likely to run into:
- Browser caching
- Site/server-side caching
1. Browser caching – what happens on your device
Can sometimes feel like it’s causing gremlins.
Every time you visit a website, your browser has to download things like images, logos, fonts and layout styles. If that same website looks pretty much the same each time you visit (which, usually, it does), your browser doesn’t need to re-download all those bits from scratch every single time. Instead, it saves a local copy – this is the browser cache. So the next time you go back, your browser can just use what it already has saved. Much faster!
Whilst this sounds great in principle, it can also be a big source of frustration. When you update your website, it sometimes won’t show the changes – because it’s still loading an old, cached version. That’s one of the reasons why, when you contact tech support for almost anything web-based, they nearly always ask you to clear your cache. (The easiest way to do this is to hold down Ctrl on your keyboard and press F5 at the same time.)
2. Site/server-side caching – what the website owner sets up
This is the kind of cache that happens on the website’s end. It’s all about speeding things up for your visitors by saving a pre-built version of a page, rather than building it fresh every time someone clicks on it. This can make a huge difference to loading times, especially for websites that run on platforms like WordPress, where pages are often generated dynamically.
How does that kind of caching work?
Let’s say your website is built using a content management system (CMS) like WordPress. Each time someone visits a page, your server might have to pull content from the database, load in the theme, assemble everything, and then send it to the browser.
With a caching plugin or system in place, your server does all that once, saves the final version, and then reuses it for future visitors. That way, your site doesn’t have to do all that work again and again. It’s a bit like batch-cooking your web pages.
Again, in theory, sounds great. In reality, it’s often used as a sledgehammer to crack a slow-loading-website-nut.
The pros of using a server-side cache on your website
Caching can be incredibly useful – but it’s not magic. Here are a few genuine benefits:
- Faster page loads: Visitors get the page quicker, especially on repeat visits or high-traffic moments.
- Reduced server load: Because you’re not generating pages from scratch every time, your server has less work to do. That can help with site stability too.
- Better user experience (and possibly better SEO): Search engines (and humans!) love fast websites. A cache can help with both.
But it’s not all sunshine and speed… Caching has its drawbacks too.
The cons of using a server-side cache on your website
- Out-of-date content: If a page is cached and then you update it, your visitors will likely see the older version for a while, unless the cache is cleared. Sometimes this has to be done manually. And, writing as the buggers who have to do this manual work, it’s a pain in the ass.
- Complexity and confusion: Caching tools often come with loads of settings, and it’s REALLY easy to break things if you’re not sure what you’re doing. We’ve seen a lot of people going for the nuclear option of implementing a cache and it has royally buggered their site, and they’ve had no idea how to fix it. We’ve even seen people implementing two caches at the same time. (That would be a bit like asking two different plumbers to come fix your boiler at the same time.)
- Doesn’t fix underlying problems: This is the big one – caching can mask performance problems, but it doesn’t solve them. If your site is slow because of bloated code, too many plugins, or huge image files, a cache might paper over the cracks – but the problems are still there underneath.
What to sort out before you start caching
Caching can give your site a nice speed boost, but it shouldn’t be the first thing you reach for. Before you start storing pre-built pages, it’s worth making sure your site isn’t being slowed down by other, more fundamental problems. Here are three biggies to check:
Is your hosting up to the job?
If your website is running on very basic (or cheap) hosting, you might be hitting the limits of what the server can handle. No amount of caching will fully make up for poor performance from the ground up. Look into whether your current hosting setup suits the amount of traffic you get and the type of site you’re running. Sometimes, a better server can make a bigger difference than any optimisation trick. If you’re not sure if it’s time to upgrade your hosting then, don’t worry, we’ve got a blog on that.
Are your images way too big?
Unoptimised images are one of the most common causes of sluggish loading times. If you’re uploading massive, high-res images straight from your phone to your website, your pages could be several megabytes larger than they need to be. Make sure you’re compressing and resizing your images properly before they go on the site – and using the right format. JPEGs aren’t where it’s at anymore. You want WebP.
We’re massive fans of the EWWW image optimiser plugin on WordPress, as it’s free and will automatically convert all of your images into WebP format. But, if you’re not on WordPress, then have a look at tools like TinyPNG to do it offline.
Want to know more about why this matters? We’ve got a blog on that too!
Is your site full of clutter?
Over time, it’s easy for websites to collect unused plugins, leftover bits of code, or third-party scripts you don’t actually need anymore. All of that adds up, and can slow things down behind the scenes. Take some time to spring-clean your site: remove anything that’s not actively helping, and check that your theme and plugins are up to date. It’s especially important to remove stuff you’re not using. If you’re not using the base theme on WordPress, ditch it. If there are plugins you don’t use anymore, then remove those too.
Don’t reach for a cache too soon
It’s tempting to install a caching plugin and hope for instant speed improvements, but caching should not be your first fix.
Before you think about caching, take a good look at what’s actually slowing your site down. Are your images optimised? Do you have unnecessary plugins or scripts loading? Is your hosting up to scratch, or are you running out of space? A cache can help, but it works best as part of a wider performance strategy – not as a sticky plaster.
To check your site loading speeds, you can use Google’s own speed checking tool at pagespeed.web.dev (it’s free).
If you’ve done a bit of housework and your site is still loading slowly, or you’re not sure where to start with all this, why not drop us a line? Our advice is free, so we can take a look at where you are with your site loading speeds, and give you some recommendations to help improve it – and it won’t cost you a penny.