The Ultimate Guide to WordPress Caching

The Ultimate Guide to WordPress Caching

Caching is a vital aspect of any website, and thanks to plugins caching in WordPress doesn’t have to take hours to set up. 

In this guide, you’ll learn how caching can help improve your website loading times. This, in turn, helps boost your conversions, improve your visitors’ experience and increase your position in search results. 

Without further ado, let’s get started!

What is Caching? 

Caching is simpler than everyone explains it. 

Think of caching this way, you’re in your high-school maths class and the teacher asks “what is 349,218.45 divided by 54.39?”. 

Everyone looks around at each other confused? Some kids bring out calculators and finally after a few minutes someone shouts out the correct answer. 

Now the teacher asks the class the same question again and this time everyone says the answer in unison, how? Because the hard work had already been done. Saying the answer isn’t slow, loading the answer is. 

That’s caching in a nutshell. A question is asked, “Please load my website?” Someone responds with “Sure! Let me figure that out”. After a few minutes the answer (the website is returned). 

Now when another person asks the same question, the middle part of figuring out the answer is skipped. The process goes from:

  1. Ask a question. 
  2. Work out the answer to a question. 
  3. Respond to the question. 

To:

  1. Ask a question. 
  2. Respond to the question. 

Taking the response from tens of seconds or minutes to under 3 seconds. Which also happens to be Google’s recommended load time

How can you sum up caching then? Caching is asking for complex information. One person doing the work and then making it available to everyone else in a fraction of the time. 

Or in other words. Storing information for quick quicker retrieval in the future. 

Thanks to cachingexplained.com for the inspiration behind this explanation.

How Can WordPress Caching Plugins Help my Site? 

Caching plugins have the sole intention of making your website load faster. Perhaps the question should be — what are the benefits of a faster loading website?

  • Improved position in search results (One of Google’s ranking factors is speed). 
  • Increased revenue for your business. After all, a 1-second delay in load time could result in a loss of $2.5 million a year! ?
  • Happier users. Think of all those times you’ve tried to load a website and been frustrated? No matter what language you speak or what country you’re from, a slow website is a universal burden.

There are some important considerations though as a caching plugin can harm your website just as much as it can help your website. 

How Can WordPress Caching Plugins Affect my Site? 

There was a time when caching plugins offered relatively few options, and they were more of a plug and play solution. Nowadays, a WordPress caching plugin can take hours to set up, given the myriad of choices they often come with. 

A long and complicated setup doesn’t just mean a few frustrating hours of configuring each option, it can mean an entirely broken website. ?

Have no fear, though, because later in this guide, we’ll cover exactly what to do should your website break.

Prerequisites Before You Install a WordPress Caching Plugin

Before we dive into what to look for in a WordPress caching plugin and how to set up caching in WordPress, we need to address the elephant in the room… the assumption that installing a caching plugin is a silver bullet to all your WordPress performance issues (hint: it isn’t!). 

What should you do before installing a WordPress Caching plugin? Make sure you have decent hosting. 

At the end of the day, you can have the most well-optimized caching setup, but if your hosting company has slow servers, there’s nothing more you can do. 

If you are looking for a new hosting company, we strongly recommend SiteGround. Plans start from just $2.95/month for the first year and offer everything you need for a good foundation for the performance of your WordPress website. 

You also want to take into account the theme you use, a bloated, slow loading theme can add seconds to your load time. 

We built Astra with performance in mind, it weighs in at less than 50KB and is blazing-fast. 

If you aren’t convinced yet? Have a read over 5 star reviews and know Astra powers in excess of 0 websites. 

What to Look for in the best WordPress Caching Plugins?

There’s a plethora of caching plugins available for WordPress. You only have to look at WordPres.org/plugins and type in “caching” to see there are over 900 results! And that’s without the premium only offerings that aren’t available via the WordPress repository. 

We’ve done the hard work for you though, and spent countless hours not only finding the best WordPress caching plugins. But also evaluating what makes a good WordPress caching plugin. 

Ease of Use

There are some fantastic free WordPress caching plugins available like WP Fastest Cache. Still, the user interface is confusing and not very clear for a beginner. 

That’s why we recommend WP Rocket. WP Rocket offers a modern, easy to understand interface, removing any setup hassles. 

One-Click-Configuration

Plugins such as WP Rocket offer one-click caching configuration and are set up out of the box. While this isn’t a must-have for everyone, if you are overwhelmed at the thought of installing a WordPress caching plugin, then one-click-configuration could be for you. 

An Easy Way to Exclude Assets

If you’ve spent even a few minutes researching caching plugins, you’ll notice a common complaint is, “I’ve activated my WordPress caching plugin, and it’s breaking my site.” 

Often a caching plugin breaks a site when scripts/styles (also known as “assets”) are cached when they shouldn’t be. 

A good caching plugin lets you exclude scripts and styles from being cached. We’d go so far to say that if a caching plugin didn’t provide the option to exclude assets, we wouldn’t use it. 

An Easy Way to Exclude Posts and Pages

The caching plugin you use must allow you to exclude posts and pages from being cached. Why?

If you run an eCommerce site using WordPress and WooCommerce and use caching to make your WooCommerce store faster, there are some things you need to do. Including excluding the shopping cart, then checkout, the account pages, and any other dynamic pages you may have. 

Why? Because if those mentioned pages end up getting cached users may see each other’s information and checkout might not work. 

Now you may be thinking “But I only have static posts, so it doesn’t matter to me”. However, we like to future proof sites. What if you decide to sell content online at a later date or create a membership website?

For these reasons, we only recommend caching plugins that provide this option out of the box. 

Minification of Assets

What exactly is minification in WordPress caching plugins? Minification or “Minify,” as you’ll often see it referred to, is an option in most popular caching plugins. 

The purpose of minification is to strip out whitespace and code comments from files, thus making them smaller.

While minifying in itself doesn’t bring huge savings, it’s still recommended to make the files as small as possible. 

Concatenation of Assets

Concat what? Don’t worry! Despite the strange name, it’s a more straightforward thing to follow than you’d think. 

Concatenation is the act of combining all files of one type into the other. For example, if you use 11 plugins and a theme, you’d have a minimum of 11 CSS files loading. That’s 11 requests the users’ browser has to make. 

By concatenating the files and combining them into one, you’ve just saved a massive ten requests! In general, on websites, the fewer requests, the better.

Support

While caching in WordPress doesn’t have to be scary, there still is a lot to configure, and it can be a daunting prospect. 

Whichever WordPress caching plugin, you pick you to want to ensure they have excellent support. 

You also want to take a look at the last time the plugin was updated to ensure that the plugin is under active development. Anything over three months is a bit long. 

Pricing

Mostly this comes down to your budget. Caching plugins are often priced in one of three ways. 

  • Premium only – Caching plugins that have no free option, like WP Rocket. 
  • Freemium – Caching plugins that have a free option with a paid upgrade for more features and faster support. 
  • Free only – Caching plugins that only have a free version with no paid version and often limited support. 

WooCommerce Support

There’s no getting away from it. WooCommerce is the premier eCommerce solution for WordPress, and due to its ever-increasing popularity, some plugins such as WPRocket have built-in integration with WooCommerce. 

If the WordPress caching plugin you want to use doesn’t come with WooCommerce support out of the box, it’s often just a case of excluding the relevant pages.

However, it can make set up a lot more straightforward if WooCommerce integration is offered out of the box. 

Membership Website Support

Some caching plugins make claims of being directly compatible with WordPress Membership plugins. I’m going to let you in on a secret… All WordPress caching plugins are compatible with WordPress Membership plugins. 

How so? As long as the caching plugin gives you an option to exclude pages, as we mentioned above, it is compatible! 

You just add the membership checkout pages to be excluded, the login page, and any other dynamic page and et voila! It’s ready to go. 

WordPress Caching Methods Explained 

There are a few different caching methods and those are:

  • Browser Caching
  • Page Caching
  • Database Caching
  • Opcode Caching 
  • CDN Caching

In this section, we’re going to take a look at what each one is. First, though, it’s important to know there are different types of caching as well. One being server-side caching and one being client-side caching. 

Server-side caching is where the content is cached on your server/website. Client-side caching is where the content is cached on the visitors’ computer, such as browser caching. 

Browser Caching

The most common method of caching. Browser caching caches the content and assets of your website in… you guessed it! The visitors’ browser. 

But just how does WordPress browser caching help your site?

By caching your website in the browser, it allows your end-user to load the website faster on subsequent visits (until they clear their cache). 

Browser caching is especially useful if you have a content-based website (without dynamic aspects) as it can significantly improve load times.

Page Caching 

By caching the contents of the page, it can be served quicker to subsequent visitors. How it works from a technical standpoint is by storing the generated page (HTML, database queries, etc.). 

Utilizing page caching is one of the simplest methods of caching with no technical knowledge required. 

Some WordPress caching plugins such as WP Rocket offer an option called “Cache Preload.” Why is this interesting? Typically your page won’t be cached until an end reader visits it. Then it’ll be generated in the cache and stored for everyone. 

The Cache Preload option allows you to cache your entire site without waiting for individual visits to those pages. 

Database Caching 

While database caching (also known as object caching) can significantly decrease the load time and increase the performance of your site, it isn’t a DIY solution unless you happen to be an experienced developer.

If you’re interested in database caching, you will undoubtedly need a specialist developer to assist you with the setup. 

But, Just What is Database Caching Anyway? 

Database caching is the method of caching queries and the results of those queries for faster access the next time that the content set is requested. 

Imagine you have a library of 1,000 books, spread across 50 shelves, and to find one book you have to go and look at every shelf and every book. Essentially that’s what some database queries need to do. 

Speeding up that request is vital to the performance of your site. Now imagine you only had to do that once and next time you memorized where the book is? Bingo! That’s precisely what database caching is. 

At the core of database caching, is an expensive query (in speed) is run and then cached to prevent the same query from running every time that data set is requested. 

Opcode Caching

WordPress is primarily built with a programming language called PHP. Every time your reader requests a page on your website that sends a request and the PHP code is then compiled to execute. 

Opcode caching enables the caching of the compiled code so that it doesn’t need to be compiled every-time. 

Opcode caching is pretty advanced stuff. Unless you have a massive website with millions of uniqueness, it’s most probably not something that is going to be worth the time or monetary investment to get set up. 

CDN Caching 

A content delivery network (CDN) works by using servers around the world to store your websites static files like images and media. 

They work by loading the content from a server that is closest to your website visitor. Eliminating any latency issues that can occur if your server is in London, and your website visitor is in Australia. 

Why WordPress Caching Plugins Can Break Your Site

Understanding why your website broke after activating your caching plugin is vital to being able to speed up your WordPress website effectively. 

Top 3 Reasons WordPress Cache Plugins Break Your Site

1. You Updated Your Plugins And Themes and Haven’t Cleared Your Cache

An often overlooked aspect of caching and caching plugins is clearing the cache created! It may sound obvious when you think about it, and yet clearing the cache is one of the leading causes of display issues. 

Before you update your plugins and themes on your WordPress website, you should clear the cache of your site and your browser cache. 

Then once you’ve successfully updated your WordPress plugins and themes, you should then clear the cache of your site and your browser cache again. 

Now when you visit the front-end of your website, everything should work correctly!

2. You’ve Enabled Concatenation For All Your Files

Concatenation is a magical thing; it reduces the number of requests a user’s browser needs to load. Speeds up your website and is all just a button click-away in the most popular WordPress caching plugins. 

However, it’s not all a bed of roses. Often enabling concatenation can break your site. Why? It may be that a script needs to load at a certain point, and the concatenated script is loading too late. Or it could be a case that the concatenation is causing an error with scripts on your site.

Whatever the cause, there is an easy way anyone of any technical ability can solve the issue of concatenation breaking websites. 

How? Trial, error, and a sprinkling of patience. Nearly all cache plugins allow you to exclude scripts from being cached or included in the concatenation. What you need to do is this:

  • Disable the caching of scripts on a plugin by plugin basis. 
  • Clear your cache after disabling the script caching for that plugin.
  • View your site, does it work? Great! If not, keep going until you find the problem plugin. 
  • Once done, re-enable caching for the files that aren’t affected. 

3. You’ve Minified Your Scripts

Minification, also referred to as minifying your files is often seen as a quick, and easy way to improve your page load times. Yet it can also completely break your website. ?

Don’t worry though! As just like with concatenation there’s an easy way to fix it. What you need to know is most well-coded plugins and themes often come with all assets already minified. 

Trying to minify already minified files (try saying that quickly) is a recipe for disaster. Here’s what you need to do if you notice any issues after minification:

  • Disable the caching of scripts on a plugin by plugin basis. 
  • Clear your cache after disabling the script caching for that plugin.
  • View your site, does it work? Great! If not, keep going until you find the problem plugin. 
  • Once done, re-enable caching for the files that aren’t affected. 

How to Setup a WordPress Caching Plugin to be Compatible With a Dynamic Website?

Setting up a caching plugin can be a breeze or a nightmare. Much of it depends on the type of site you’re setting up caching on, and of course, which caching plugin you pick. 

In this section, I’m going to show you how to set up caching for dynamic websites using WP Fastest Cache and WP Rocket.

Just What is a Dynamic Website?

A dynamic website is any website that isn’t only static. A dynamic website may include any of the following functionality: 

  • Login/Logout – A cornerstone of a dynamic website is login and logout functionality. As you’ve probably guessed all WordPress websites are by their nature dynamic. 
  • eCommerce – Any website that sells digital or physical products using a plugin like WooCommerce is a dynamic website.
  • API based websites – If you pull in data from a third-party resource there’s a good chance your website is dynamic and caching the data could result in outdated data being displayed to your users. 

How to Set Up WP Rocket for Your Dynamic Website

Step 1. Install and Activate WP Rocket

Once you’ve installed and activated the plugin you’ll see a couple of things. 

  1. It’ll automatically preload the cache for you. 
  2. Page caching is automatically enabled out of the box. 
wp rocket dashboard after completing the set up

Step 2. Excluding Your Dynamic Pages

WP Rocket already does a lot of the hard work for us.

If you run an eCommerce website on WordPress using WooCommerce, BigCommerce, Easy Digital Downloads, iThemes Exchange, Jigoshop, or WP Shop — WP Rocket will automatically exclude the cart, checkout, and account pages. 

Simple right? If you run a membership site or have other types of content you need to exclude head over to your wp-admin > Settings > WP Rocket > Advanced and add the URLs under the “Never Cache URLs” area. 

never cache urls warning screen

As you can see, setting up dynamic content compatible caching with WP Rocket is a breeze. User-friendly and straightforward.

How to set up WP Fastest Cache for Your Dynamic Website

Step 1. Install and Activate WP Fastest Cache 

Unlike WP Rocket, WP Fastest Cache doesn’t pre-set anything so, this is going to take a bit more time! The first thing you’ll notice is how many options there are within the user interface:

wp fastest cache options

Step 2. Enable the Cache 

In your wp-admin > WP Fastest Cache, check the box to enable the cache system. 

Now the cache is enabled you need to exclude your dynamic content. 

Step 3. Excluding Your Dynamic Content from WP Fastest Cache 

If you’re running a WooCommerce site you don’t need to take any further action. WP Fastest Cache is compatible with WooCommerce out of the box. 

However, if you are running a membership site you’ll need to exclude your account and payment pages. This can be done in your wp-admin > WP Fastest Cache > Exclude.

wp fastest cache exclude options

Then click on “Add New Rule” which will open up the wizard to exclude a page like this:

wp rocket exclude page wizard

In the first dropdown, select “Is Equal To,” and then in the second box, enter the exact URL you want to exclude from caching and click “Save.” 

The WP Fastest Cache setup and interface definitely isn’t as slick as the one provided by WP Rocket. However, you can still achieve the same result with excluding pages, and it’s free versus premium, perfect for if you’re on a budget. 

Top 5 WordPress Caching Plugins

As we’ve already explored, there are literally hundreds of caching plugins. Here are our top 5, along with the positives and negatives of each. 

1. WP Rocket

WP Rocket homepage for plugin download

WP Rocket is a premium-only caching plugin for WordPress. As the plugin is premium, only there’s a strong focus on high-quality support. And the team behind it are more than happy to help with any queries or issues that may arise. 

WP Rocket Positives

  • One-click configuration.
  • Automatic support for WooCommerce.
  • Cache Preloading.
  • Lazy loading image support.
  • Top-quality support.

WP Rocket Negatives 

  • Premium only. 
  • No free trial. 

Apart from that WP Rocket is our favorite WordPress caching plugin.

WP Rocket Pricing

WP Rocket offers a clear and transparent pricing structure, no tricks or additional add-ons to buy after the fact. 

Pricing for 1 website is $49, pricing for 3 websites is $99 and pricing for unlimited websites is $249. 

WP Rocket Verdict

In our opinion, WP Rocket is, without a doubt, the best WordPress caching plugin available. Easy to set up, great support, and it offers everything you need from a caching plugin and nothing you don’t.

2. WP Super Cache 

WP Super Cache download page

WP Super Cache is from the makers of WordPress.com (Automattic) who’s founder Matt, is a co-founder of WordPress.org open-source software. 

WP Super Cache is extremely popular, with over 2+ million active installs.

WP Super Cache Positives

  • Free
  • Maintained by the parent company of WordPress.com
  • CDN Support
  • Cache preload support
  • Developer Friendly

WP Super Cache Negatives

The main negative for WP Super Cache is the lack of support. While some Automattic employees do reply in the forums to queries, the speed and premium support you get from a paid plugin just aren’t there. 

Also, unlike most free plugins that have a premium option, there isn’t such an option here. If you get stuck, you’ll need to hire an independent freelancer. 

WP Super Cache Pricing 

WP Super Cache is entirely free with no paid options. 

WP Super Cache Verdict

WP Super Cache is a great caching plugin if you’re on a budget. However, be aware of the limited support provided and the fact that even if you want to, you can’t pay for help from the developers. 

3. W3 Total Cache

W3 Total Cache download page

W3 Total Cache has been one of the most popular caching plugins for WordPress for a while, with a million+ active installs. 

However, there was some controversy over the past year with poor support from the plugin author and some paying users not receiving replies for months. 

The plugin was recently by BoldGrid a company that has recently acquired a string of WordPress plugins. WPTavern wrote a great writeup of the acquisition.

W3 Total Cache Positives 

  • Everything you could need from a caching plugin. 
  • Database caching support. 

W3 Total Cache Negatives 

  • Track record of poor customer support. 
  • Issues with slow updates in the past year. 
  • Overwhelming plugin interface with notices and non-important things you don’t need. 
  • Confusing way to purchase pro version (W3 Total Cache Pro can only be purchased from within the free plugin).

W3 Total Cache Pricing

Overall the pricing structure for W3 Total Cache is straightforward, there’s one-tier which is $99/year for one site. 

However, there’s no multi-site discount. For the cost of W3 Total Cache Pro for 3 sites, you could get an unlimited license for WP Rocket.

W3 Total Cache Verdict 

While W3 Total Cache is still an excellent plugin for WordPress caching, it’s no longer the de-facto plugin, and you should seriously consider some of the other WordPress caching plugins available.

4. WP Fastest Cache

WP Fastest Cache download page

WP Fastest Cache is another WordPress caching plugin with over a million active installs. 

While the plugin itself works well and provides some of the best results, it can be challenging to get to grips with for a beginner. 

The plugin interface is old fashioned and not user-friendly, and many of the features you’d find for free in other caching plugins are locked to the pro version. 

Despite this, it’s still one of our favorite caching plugins for WordPress. 

WP Fastest Cache Positives

  • Well supported.
  • One-time payment for the Pro version (no yearly renewals).
  • Core caching options available for free.

WP Fastest Cache Negatives

  • Many features are locked to the Pro version. 
  • Difficult to use for beginners. 
  • Outdated interface. 

WP Fastest Cache Pricing 

WP Fastest Cache has an unusual pricing structure for a WordPress plugin, as it’s a one time fee. That means you can pick the license for the number of sites you want and never pay another penny! 

WP Fastest Cache Verdict

As long as you aren’t looking for an up-to-the-minute interface, WP Fastest Cache is a fantastic all-round caching solution for your WordPress website.

Fair transparent pricing combined with a wide range of functionality. 

5. Hummingbird

Hummingbird caching plugin download page

Hummingbird by WPMU DEV is the newest caching plugin we’ve showcased here. While it’s new, it certainly isn’t lacking in features and has a modern, clean interface. 

WPMU DEV themselves are no strangers to the WordPress plugin market. In fact, they are one of the most popular premium WordPress plugin companies. 

They offer a suite of plugins related to caching, security, backups, and the maintenance of your website.

Hummingbird Positives 

  • Clean modern interface.
  • Easy to use.
  • Everything you need is available in the free version.
  • Fast support. 
  • Lazy load images with free Smush integration.

Hummingbird Negatives

  • Expensive pricing model if you only want to use Hummingbird. 

Hummingbird Pricing 

WPMU DEV only sells Hummingbird Pro as a bundle with all their other plugins and services including, security, backups, and hosting. For $49/month for unlimited sites and $30/month of site hosting credit is included. 

Hummingbird Verdict

Even though Hummingbird is one of the newer players in the market, WPMU DEV has released a feature-rich plugin that includes a vast array of features. 

With free support provided you most probably won’t even need to upgrade to Hummingbird Pro. 

Wrapping up

Phew! That was a lot of content. We hope you enjoyed the article! Caching doesn’t have to be difficult or complex and knowing what to look for and how to resolve issues before you dive in, is a sure-fire way to success.

Do you already use a WordPress caching plugin? 

Have you encountered some of the issues mentioned here when using a WordPress caching plugin? Let us know in the comments below.

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