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How WordPress Caching Is Done | Top 10 Webster Plugins

When it comes to web performance, WordPress caching plugins are just one of those things that every site owner or webmaster has to deal with at one point or another. Of course, we all love WordPress, but it’s definitely not the only fastest platform.

Especially if you compare it to a completely static site. One reason for this is simply because it’s built on PHP which can only execute things so fast. We saw some massive improvements with PHP 7.4 and PHP 8.0, but if you don’t properly cache your site it can still come to a crawl.

How is WordPress Caching done?

By definition, when we talk of WordPress caching, it’s the process of storing resources from one request — and then reusing those resources for subsequent requests. Basically, it reduces the amount of work required to generate a page view.

What is Caching?

Have you ever heard the phrase “clear your cache” and wondered about this voodoo magic?  In most situations, people are probably referring to your browser cache so that you can see the latest data or content on a website or application.

In cloud computing, Caching allows you to efficiently reuse previously retrieved or computed data. While a cache is a high-speed data storage layer that stores a subset of data, typically transient in nature. So that future requests for that data are served up faster. Unlike when it’s possibly accessed from the data’s primary storage location.

The data in a cache is generally stored in fast access hardware such as RAM (Random-access memory) and may also be used in correlation with a software component. A cache’s primary purpose is to increase data retrieval performance by reducing the need to access the underlying slower storage layer.

Trading off capacity for speed, a cache typically stores a subset of data transiently, in contrast to databases whose data is usually complete and durable. I guess I talk about this in detail in a previous blog. So, for now, let’s focus our interest on WordPress caching.

How is WordPress Caching done?

First of all, WordPress sites are so dynamic. Meaning that they’ll always use a database, have complicated PHP scripts, and they’re ever-changing. All of your posts, comments, and other information are stored in this database. And every time you or your site users load the page, your blog has to figure out what page (or post) you’re all trying to view.

As a result, it’ll then pull that data content out of the database to display it for you or your site visitors. It does that on every single page load. But, that’s a lot of work! Right? Well, that’s where WordPress caching plugins come in handy — more on that later.

The WordPress caching plugins are used as the tools that provide a way of improving your general website performance. If the site is getting too many hits, you can enable WordPress caching by installing a cache plugin. And by purging the cache, essentially means re-caching all previously cached data.

Related Topic: How to Purge Cache and Keep your Website content fresh

This means the old ones are deleted and new ones are created or regenerated — it typically takes place based on a number of protocols. Some of which are included when a new comment is posted, a new post is published, or when an old post is updated.

What a caching plugin does (usually) is generate static, HTML copies of your pages. So that when the page gets viewed, it saves a copy of that page in a static form. And then it displays that static HTML copy to your users. That way it doesn’t have to check the database every single time. It saves time and resources when loading pages.

This can be why sometimes you make a change to one of your posts and you don’t see the changes instantly. It means you’re still viewing the old “copy” instead of a live version that gets retrieved from the database on the fly.

Types of WordPress Cache

In short, WordPress caching is when a website is requested repeatedly from different clients. And then reusing the previously generated data (or requests such as database queries) to speed up new requests. We can also not forget about the process of purging the cache.

Some of the major benefits of WordPress caching plugins include speeding up the website and better search engine rankings. It also helps save some of your server’s resource consumption. And now let’s dive into the basic types of WordPress cache you’ll run into on a regular basis.

Understanding what each layer of caching does will help you troubleshoot issues related to cache. As well as ensures your site will run smoothly. There are two primary types of caching protocols available, based on the client-server model. They’re Client-Side Caching and Server-Side Caching.

Having said that, let’s look at how they work below. So, that you get a clear picture of why WordPress caching is important.

1. Client-Side Caching

When we talk of Client-Side Caching, a website contains a lot of non-textual, static data, such as images, CSS, and Javascript files. Once they’re downloaded, your browser is smart enough not to re-download them every time you hit the F5 button.

It simply serves that data from the local cache — i.e. the cached data saved in your computer’s hard disk. That’s why it’s recommended to clean your browser’s cache every once in a while. Since it saves a lot of space and improves performance. This process of reusing the cached data from the client’s computer (or the client’s end) is known as client-side caching.

Almost every modern website uses it and every browser supports it too. Eventually, client-side caching greatly helps prevent data redundancy. For example, downloading the same data over and over again — while saving a lot of server resources.

1.1. Bytecode Cache

At the client-side caching level, there’s also a Bytecode cache that stores compiled PHP code. So that the next time it is used the compilation step can be skipped. At Kinsta, for instance, they’ve enabled OPcache in PHP 7.2, 7.3, and 7.4. And they’ll even enable it in newer versions of PHP as they are released on their platform.

When a PHP file or script is processed it first has to be compiled into machine-readable opcode. What OPcache does is store the converted opcode. So that PHP will be able to skip the compilation step the next time that specific file or script is needed. Using OPcache significantly improves the performance of PHP.

However, it also means that changes to PHP files are not reflected immediately. And that’s why, for this reason, OPcache is disabled on staging sites. You can read and learn more about how OPcache speeds up PHP applications in detail.

2. Server-Side Caching

Caching at the server is known as Server-Side Caching. Whereby, for the server-side caching, it includes various caching protocols that are used in CMS platforms like WordPress for caching. And in general, they’re listed as page caching, database query caching, object-based caching, and opcode caching.

Before I elaborate on them further, you can mainly consider a CDN (Content Delivery Network) solution (like Cloudflare) in this case. As the main cache handler for a majority of CMS platforms. CDN caching stores website files (such as JavaScript, CSS, and media files) out on a content delivery network.

This allows for faster delivery to users who are geographically distant from the host server location. And when someone tries to reach a website, those files are delivered from the CDN — rather than having to be delivered from the server that actually hosts the website.

A CDN offers 4 primary benefits:
  • Reduces the server resources required to load a website.
  • Since the CDN is doing the work, the webserver doesn’t have to.
  • Allows resources to be delivered from locations all around the world.
  • Speeds up website performance for users who are geographically distant from the web host.

There are two basic types of CDNs: Those that are simply CDNs and those that offer a CDN along with security features.

A few common examples of each include:
  • Standard CDN: Kinsta CDN, Stackpath, CloudFront (KeyCDN).
  • CDN plus security: Cloudflare, Sucuri, Akamai (optionally).

The first type of CDN is set up by creating CDN URLs which are used to access the website resources.

The exact way this is enabled varies from one CDN to the next. The basic idea is that URLs for static resources will be changed to the CDN URL. So that the resources are pulled from the CDN. A standard CDN typically only caches static files like JS, CSS, and media files.

Related Topic: How to Choose a Web Hosting Solution Plan for Your Site

The second type of CDN serves as a full proxy server. What this means is that every request has to go across the provider’s servers before arriving at the CDN servers. In that case, this is enabled by using the CDN provider’s nameservers, Perse.

So that the CDN provider has full control of the website DNS. And as a result, this allows the provider to do a lot of things that a simple CDN cannot do. Such as filter out traffic from bad IPs, offer DoS/DDoS protection, etc. Or even store a full page cache out on the CDN. Now, let’s look at the other server-side caching features:

2.1. Page caching

Of all the caching protocols, page caching is the simplest. It simply refers to the process of saving the dynamically generated HTML files in the server’s hard disk or memory (RAM). And that’s the reason why it’s known as the Cache.

Then it will be serving from the cache (i.e. reusing previously generated data) whenever a request is made. This saves the overhead of executing PHP code and MySQL database queries.

2.2. Database query caching

As for the database query caching, the databases will consume more resources. They can be called the heart of every company. The database is used to store, update, and deliver data efficiently. Since they’re usually huge, each query takes time (usually in the order of a few hundred microseconds).

In the case of databases, the better the hardware, the faster the query result generation. Since WordPress is heavily reliant on its database, it makes a query many times. When data isn’t being altered in the database and queries are made to retrieve the same data it is like re-downloading the same images.

Therefore, saving the results of a query in the local storage will save time and resources. The saving of database queries results in local storage which is called database caching and is one of the fundamental factors in WordPress caching.

When the database is updated, like when a post is updated or published, or comment is submitted, it is required that the previously saved database cache be deleted. And that’s when re-caching the database query results again.

2.3. Object-based caching

WordPress has an internal caching system that includes several subsystems. Including the Caching API, Object Cache, and Transient API.

The WordPress core allows plugins to control this caching system — to reduce the number of database calls.

2.4. Opcode caching

Just like database caching, opcode caching refers to the saving of the compiled PHP code between every request. PHP is an object-oriented programming language.

For a PHP code to execute, the PHP compiler must compile the code first. And then generate the executable code for the webserver to execute.

Why should you use the WordPress Caching Plugins?

Well, that’s so simple! WordPress Caching Plugins helps make the websites built on its platform work evenly faster — thus, caching reduces the load on the webserver. And as such, that’s why every site owner or webmaster should strive to use as many caching solutions as possible.

In addition, in the case of a CDN platform (like Cloudflare), its caching solution also reduces the amount of server bandwidth required to generate a pageview. By storing static resources external from that of your WordPress host. But, at times, no WordPress cache plugins are needed if you’re hosted by a platform like Kinsta.

Related Topic: Why Cloudflare is the Best for Web Performance & Security

Therefore, do you want to increase the speed of your WordPress website? Using a caching plugin on your website is one of the best ways to ensure your website loads faster. Statistically speaking, nearly half of your website’s audience expects your site to load in less than 3 seconds.

So it comes as no surprise that Google continues to emphasize site speed in its search algorithm. The higher the page speed, the better your search rankings, and the more organic traffic you can attract. Having said that, out there are some WordPress plugins (both free & premium) you can consider for your site caching.

Top 10 Best WordPress Cache Plugins:
  1. Breeze: — Free WordPress Cache Plugin
  2. WP Rocket: — Most Popular Premium Cache Plugin
  3. WP-Optimize: — All-in-one WordPress Optimization Plugin
  4. SG Optimizer: — Free WordPress Plugin by SiteGround
  5. WP Super Cache: — Cache Plugin from
  6. W3 Total Cache: — Developer Friendly WordPress Cache Plugin
  7. WP Fastest Cache: — WordPress Cache Plugin With Minimal Configuration
  8. Comet Cache: — Free WordPress Caching Plugin
  9. Cache Enabler: — Best Lightweight WordPress Cache Plugin
  10. Hyper Cache: — Yet Another Free WordPress Cache

And now, everyone knows how important a fast website is. The quickest and most effective way to speed up your page is by using caching tools and plugins. Just like the ones listed above. But, of course, there are other more up and running plugins that didn’t manage on our list.

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Therefore, if you’ll have additional contributions, you can let us know in our comments section. So that we include them on the list. Wouldn’t it be nice if you didn’t have to worry about figuring out which WordPress caching plugins are the best? You’ve all the answers now. But, test each of the features they offer to make an informed decision.

A New Webmaster Recommendations

Definitely, it’s worth using a caching plugin! Most tools have similar features, but the free plugins are somehow more efficient than paid ones. This is mainly due to additional features such as the lazy load of images, delayed loading of scripts, font optimization, and generation of critical CSS.

Further advantages of the premium plugins are the support and the continuous development and improvement of the functions. But is it really worth it to invest money? Yes and no. As the test shows, even the free plugins deliver very good speed values. I, therefore, recommend Breeze or Hummingbird Page Speed Optimization to the cost-conscious normal user.

Both are absolutely easy to use, cost nothing and do a good job. If you would like to have a super-fast website and are willing to invest money, WP Rocket is the right choice for you. The plugin makes the page really fast and you do not have to spend too much time on the right settings.

Related Topic: How to Create a New WordPress Site | Free Ultimate Guide

Therefore, it is also suitable for inexperienced users. And if there are problems, you can always contact the fast and helpful support. There is also extensive documentation and help topics on the website. Above all, it’s quite difficult to single out any of the aforementioned plugins for caching.

Besides, there are other cache plugins that are available for use on the WordPress plugins directory. However, there are only a few marginal benefits that separate each of the plugins. So, my advice to you would be to find out what your requirements are. And then test the plugins in the list above to see which suits you the best.

Final Words,

Today, the Internet is all about speed! In order to rank well on search engines, one of the few attributes of the website is that it should be fast. Nobody wants to use a website that is slow. It drives away potential customers and maybe some of the users would simply click the back button before even viewing it.

In reality, a fast-loading site is kind of a ‘make or break’ big deal, especially if you build sites for clients or run an online business. Hence, the importance of being cached up. But, keeping your website running at blazing-fast speeds requires a superheroic effort.

That’s why we employ superheroes like Hummingbird and WPSmush to keep your site and your images optimized. It’s also why we publish loads of content on ways to improve WordPress performance and boost your site’s speed.

Related Topic: How to Fix 5xx Server Errors | A Simple Step-by-step Guide

That said, before even discovering the best WordPress cache plugins, one of the first things to know is the current situation of your website — using a free service like Pingdom Tools.

One of the improvements you will be recommended by Pingdom Tools is precisely to install a WordPress cache plugin. Not forgetting, the website allows you to get information on the loading time of your pages and the improvements you can make.

Finally, please, let us know what you think about the WordPress Caching guide above. Whereby, you can share some of your additional thoughts and questions in our comments section below. You can also Contact Us if you’ll need more support or help.

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