Website Caching: How It Works and Why It Speeds Up Your Site

Website caching is extremely important and impacts the speed of the website. With the help of this method, specific copies of the content are stored in a more accessible location in such a way that the load of the host server is significantly minimized.

Without access to caching, the user’s browser request content of the specific website every time they enter this resource. With caching, all the resources are stored closer to the location, so the process of accessing is significantly speeded up.

Cache can be on the server or client side. On the server side, the necessary information is stored on specific servers within a CDN (Content Delivery Network), and on the client side, the data is specifically located in the user’s web browser.

In this article, we will explain all the details related to the cache, its usage, and management, to minimize possible issues and speed up website loading.

Core principles of cache functioning

The effectiveness of cache lies in the principle that minimizes the necessity to repeatedly get the data from the same server. Here are the major steps of the process functioning:

• Initial request. Once the user tries to interact with the needed website for the first time, the browser sends an initial HTTP request to the server, and then the webpage is built.
• Storage of the cache. After this initial request browser stores received information in the cache. The time-to-live interval is determined for this data and the duration of its storage in cache.
• Following requests. Once the user tries to enter the same webpage, the browser checks whether there is any information in the cache. If this information is still stored in cache, then the browser serves the cached copy of the webpage. If there is no such information in the cache, then the request occurs again with the original server, and this information is stored in the cache.  
• Validity checks. To check whether stored information in the cache is still valid, the HTTP request is sent, and if any outdated data is noticed, then updated resources are immediately sent to the user’s browser.

How does the cached content get delivered?

Cached content is delivered way faster because there is no necessity to make a direct request from the original server. Because there is no need to repeat the same request to the same website, it is possible to get quicker access to the needed web page by using previously stored information. This is extremely helpful when you are trying to enter static web pages.

Getting information from the cache that is stored on your device is way faster than waiting for the request from the remote server. And even if the cache isn’t stored on the local user’s device, it will be stored on the CDN that is still located closer to the user.

The importance of website caching

The proper management of website caching is extremely important and impacts search engine ranking, general performance, and user experience. Here are a couple of reasons why caching is needed:

• Faster loading time of the webpages. Because the information is stored on the local device, users don’t need to wait for the information to be received from the original server.
• Minimization of the server load. Because the information is received from the local device, but not from the original server, fewer requests are made. So, fewer resources of the original server are used, and it can deal with other traffic more effectively.
• Minimization of the used bandwidth. Due to the cache less information is transferred, which means users are saving their mobile data and website owners are minimizing bandwidth consumption.
• Better SEO. In the Google ranking algorithms, loading speed is considered to be a crucial factor, so efficient caching can directly impact the website ranking.
• Improved content availability. Even when the original website isn’t accessible for any reason, users still have a possibility to access cashed version.
• Improved conversion rates. The speed of some websites can directly impact the conversion rate, especially if we are talking about e-commerce platforms.  

Main Types of Website Caching

Based on the location of the storage, there are various types of caching, but mainly, there are only 2 major categories: server-side and client-side.

Overview of Client-side Caching

Client-side cache is stored on the local machine of the user and mainly in the browser cache. That means all the management processes are done via the web browser. Usually, this approach is automatically functioning, but there are some manual options of management as well.

Website owners can also somehow manage this type of cache via server-side storage. For instance, site administrators can force the storage of new files even if there is a longer cache duration. The main issues with such a cache are its limitations based on the device's storage space.

Understanding of server-side caching

Server cache is a term that relates to several other caching types. Here are the major categories that you should be aware of:

• CDN cache. This type of cache is stored with the help of CDN, which have distributed network of servers and the closest one is chosen based on the user’s actual geographical location. This speeds up the process of content delivery because there is no need to contact the original server all the time.
• Opcode caching. This technique functions by saving the compiled code of such languages as, for instance, PHP to exclude the necessity of re-compiling.
• Object caching. This type of caching stores complex operations, such as database queries and others, in the host’s memory. The process is conducted with the use of such tools as Redis.
•  Fragment caching. Only the storage of specific elements, such as widgets or titles, is done.
• Full-page caching. The entire copy of the web page is saved in cache.

Clearing website cache

The usage of the outdated cache might negatively impact general user experience, because there will be access to outdated information and other troubles. So, the major recommendation is to clear the cache regularly.

The methods of clearing the cache

Here, we will talk specifically about WordPress websites. To clear cache on such platforms, it is highly recommended to use plugins such as WP Super Cache, LiteSpeed, or WP Rocket.

Based on the used option, the process of clearing might differ a little. Start by entering the WP admin dashboard and choosing the cache that you need to purge. For instance, you can delete pages cache, the front page, the opcode cache, all CSS cache, and others.

Deleting cache on non-WordPress platforms  

If you need to delete cache from non-WP platforms, this can be done via the hosting control panel. This option also depends on the used control panel and chosen web hosting provider.

For instance, if you are using cPanel, it is possible to complete this process by opening website information via File Manager and simply clearing cache folders. On other control panels, most often you will need to enter the dashboard and find the clear cache option there. Also, it is possible to delete the cache from a specific webpage or set up an automatic process so that all the pages will be up-to-date.

Process of Deleting browser cache

The deletion of the browser’s cache can be conducted manually just from the history menu in a couple of clicks. When doing it manually, you can select the needed time range and specify the type of cache you need to delete, whether it is a browsing history, images/files, or cookies/other site information.

Another great option is to force the browser to load directly from the original server. This can be done by pressing Ctrl + F5 (Windows) or Cmd + Shift + R (macOS).

How can cache impact website speed?

Because of the website cache, it is possible to impact the loading time, improve conversion rates, get better SEO signals, and improve UX in general. To check whether cache really matters for your website speed improvement, you can use such tools as Google PageSpeed Insights or GTmetrix. Conduct 2 tests, one before clearing and one after clearing the cache, so you can visually notice the difference for your project.

Caching won’t fix all the issues, but it surely shows the instant result that you can measure and notice right away.