What Is Caching? How Does It Work?

Have you ever heard the word Cache or Caching in the web hosting industry? You might have heard of Caching Plugins also. I’m sure you did. 

But have you ever thought, what are they and how do they work? If not, be with me throughout the article, as I will explain in simple English.

But before that, I would like to explain the working of Cache Memory in your device as it is important to understand the whole process.

What is Cache Memory?

If I have to say in simple words, cache memory is a reserved storage area that contains temporary data from the apps, browsers, or websites to help them load faster. Whereas caching is the method of storing copies of this information. The cache is also often called Junk Files.

The information stored as the caches could be files, images, or scripts that the user might have opened while opening any app or website. 

These caches play a vital role in loading the document next time when you access them. As caches are the temporary storage location that keeps the data to themselves, you don’t need to fetch it to access them. Therefore, it helps you to retrieve the previous data quickly. Thus the information loads faster. 

A very similar thing happens with website caching also. But here, we can have three different types of caching, namely site/page, browser, and server caching. 

Let’s discuss them in detail.

Site Caching

Site caching or page caching is a method to store data temporarily when someone visits a website for the first time. 

This method is very similar to human memory. 

For example, it is difficult to find an unknown place for the first time. However, it becomes easier to reach the same place once you have already visited it before. Similarly, when you visit a website for the first time, some information is stored in your device’s cache memory that it can recall quickly afterward. This leads to faster loading of your website. Please understand this method doesn’t help on the first visit.

As you can see, this method is entirely dependent on the client-side device configuration, and as a webmaster or a developer, you have limited control over it. You only can inform the device how long to store the data on a client-side device.

Browser Caching

Browser caching is another client-side caching methodology. However, here the files are stored in browser memory instead of cache memory.

Modern browsers like Google Chrome, Firefox, Microsoft Edge, Safari can store HTML pages, CSS files, JavaScripts, images, and many other multimedia files in a special location assigned as browser cache memory. This memory complements device cache memory as it can store minimal information.

A website can communicate with this memory and instruct them what to store and how long to retain them. As an end-user, you can flush this data whenever you want. If you have ever cleaned your browsing history, you actually have washed browser cache memory.

Server Cache

Server caching is very similar to page caching, but here the information is stored on the website server instead of the client’s device. As a webmaster or developer, you have complete control of the caching process.

Server caching is particularly helpful for dynamic websites as it reduces server operation significantly. 

There are several plugins available for server caching. They either work on the server level or the application level. A simple example could be the WordPress caching plugin.

A very naive explanation could be that such plugins generate static web pages corresponding to your website pages. Thus it reduces PHP and database operations significantly, making your website fast.

There are mainly three different types of server caching;

  1. Object Caching: Stores database queries so that they can be retrieved easily.
  2. Opcode Caching: Compiles and stores PHP codes so that they can be executed faster.
  3. CDN Caching: Distributes website assets among different geographical locations. The browser and CDNs collaborate so that the local CDNs receive a request from the browser, which reduces the data travel distance and makes transfer resources faster. Read this article for a better understanding of this methodology.

Final Words

It is evident that when you visit a new website, the browser takes time to download the data to load and show them. It is a time-consuming process. Caching can speed up this process significantly.

Moreover, it reduces server execution costs significantly. A properly cached server can serve more users than an ill-configured server with the same resources.

If you are using WordPress CMS, there are several caching plugins available for you. Furthermore, there are several managed WordPress vendors who include server-side caching facilities. This is a better option than PHP plugins.

So, next time when choosing your web host, ask for this facility. Your visitors will definitely appreciate your effort.

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