A Guide To WordPress Caching And Why It Is So Important

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As a WordPress user, you must have come across articles regarding WordPress speed optimization. Speeding up a WordPress site involves many factors, and among them caching is an extremely important factor.

Caching when implemented properly can reduce the load times of your WordPress site which can further contribute to SEO rankings and deliver a better user experience.

In order to take full advantage of caching in WordPress, it is important to understand its mechanism and learn the effective ways of implementing it.

How Caching Works?

Caching is temporary storage that keeps the copy of static web pages to reduce load time. Typically when a user visits your WordPress site, he sends a request to your web server for every single action he performs on your website.

In return, your web server is being called by your WordPress to entertain each and every request of your site visitor. These back and forth transactions can cause delays if the server is busy handling traffic or if the distance between the visitor and server is too wide.

Sometimes a user is requesting for same requests over and over again. For example, the header or footer of a site does not get updated as posts do and when it's loaded ones it does not need to be fetched from the server until it's changed. In the case of dynamic content, which updates often, the caching mechanism is capable to clear the old cache and generate a new one with updated content.

Caching keeps a copy of HTML files already been served once from the server inside its RAM and instantly delivers it to the user without any processing like it did the first time. This exchange is faster and puts less burden on the hosting server.

Types of Caching

If you run a WordPress site then you should keep two types of caching in your mind.

  1. Server Side Caching
  2. Client Side Caching

Server caching is performed on the server level and browser caching is done on the client side. Let’s explore each option to understand its effect on website speed.

1. Server Side Caching

Caching done at the server level is associated with server-side caching. It stores the requests previously requested by the client and instead of going through the whole process again and simply delivers the end result. This makes the data fetching faster and improves overall site performance. WordPress hosts like Kinsta and Cloudways do server-side caching.

Here we also need to understand two common methods: Object Caching and Full Page Caching.

Object Cache: Instead of caching the whole page, the object cache only caches the repeated query results. Various queries are made to the database to fetch the required data requested by the user. Object cache stores the result of these frequently requested queries for faster response.

Full Page Cache: Unlike object cache, this method stores a full HTML page or complete view requested by the user. This method makes the page load faster as it does not need to generate a web page for every subsequent visit.

Hosting Caching Mechanism

Many hosting providers offer optimized hosting which has built-in capabilities for server-side caching. These providers optimized their servers on core levels which is more effective than using any WordPress plugin.

An example of this can be seen at Cloudways which is a managed WordPress cloud hosting. Their stack is well equipped with an advanced caching mechanism that produces faster websites. Let’s examine what tools they have implemented for caching and what functionalities they perform.

Nginx

This is a very fast web server that is famous for reverse proxying, caching and load balancing. Nginx is being used by the majority of high traffic sites as it can handle a large number of concurrent users. It's a lightweight high performing web server built to handle thousands of connections.

Varnish Cache

Just like Nginx, Varnish is also a reverse proxy caching. This is considered to be extremely fast and it said to boost website speed to very high levels. Cloudways users can also apply custom varnish rules through their platform which is necessary for WooCommerce and WPML sites.

Redis

This is a dataset server that is used to store high-level data types such as strings, hashes, lists, sets, and bitmaps, etc. This is implemented to cater high volume of read and write operations.

Memcached

Memcached deals in caching data and objects in RAM to deliver fast data without connecting to an external data source or API every time the user makes a request.

2. Client Side Caching

Caching handled at the user browser is associated with client-side caching. Typically when a user browses a web page, he is not only loading the content but also the JavaScript and Stylesheet files working behind the scenes of the web page.

Browser Caching

Browser caching is the most effective method for client-side caching. When the user visits a web page in a browser, it caches the resources necessary to display the page such as JavaScript files, styles sheets, and media content. This content is stored temporarily in the browser and is served directly from the local storage instead of requesting again from the webserver.

Implementing Caching in WordPress

WordPress is a dynamic platform that supports data-rich functionalities and content-rich themes. There is a lot of room to cache this content to achieve faster-loaded pages. We already have seen how we can leverage from the server and client-side caching. Let’s see how WordPress plugins can help us in building an effective client-side caching mechanism.

WordPress Caching Plugins

There are many WordPress caching plugins that claim to make your site load faster. We have listed down three popular WordPress cache plugins.

Breeze

breeze wordpress caching plugin

Breeze is a free lightweight plugin by Cloudways. It offers all the features necessary for client-side caching.

The plugin offers the following highlighted features:

  • Minification of CSS, JS, HTML
  • Gzip Compression
  • Browser Caching
  • Grouping of CSS and JS
  • Database Optimization
  • Varnish Rules

WP Rocket

wp rocket cache settings

WP Rocket is a high performing caching plugin which is easy to set up and comes with all basic and advanced features to manage client-side caching on your WordPress site. Some of WP Rocket's features are:

  • Cache Preloading
  • Static File Compression
  • Page Caching
  • Gzip Compression
  • Database Optimization
  • Browser Caching

W3 Total Cache

W3 Total Cache wordpress caching plugin

With over one million active installations, W3 Total Cache plugin is one of the popular WordPress caching plugin.

The plugin can be downloaded free from WordPress.org and can easily be configured through WordPress dashboard. It has separate sections for each functionality. Some of the highlighted features are:

  • Page Cache
  • Database Cache
  • Minification
  • Object Cache
  • Browser Cache
  • Cookie Groups

Advantages of WordPress Caching

There are many advantages of implementing proper caching on your WordPress site.

  • It improves the speed of your WordPress site as well as enhance user experience.
  • Since the server is not pinged for every single request every time, it reduces the load on hosting server.
  • As well all know that Google loves faster sites. Therefore, it also improves the SEO ranking.
  • On client side, bandwidth is also saved as it leverages from caches content stored in local memory rather than fetching data directly from servers.

If you still have not implemented caching on your WordPress site, then I suggest you do so by following this article. Make sure to take a full backup of your site as it has been seen that after WordPress site breaks after implementing caching. Also, test your site performance before and after implementing caching to see the difference it can bring to your WordPress site.

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