• 23 May 2024

Website caching is one of the most useful technologies available. In a short time, this technology will make your website very fast, which will increase its SEO score and increase user satisfaction.

This article will teach you about website caching and how it is implemented on websites.

What Is Cache?

Although the exact details of the cache are very complex, the basic idea is straightforward. Let’s take an example:

If we ask you the result of 5 x 3, your answer will be 15. You definitely don’t calculate to answer our question. You have calculated it many times in your life, and you don’t need to calculate anymore. You probably remember the result quickly and without any complex mental process. Well, this is exactly the process that happens in caching.

Websites are typically viewed hundreds, thousands, or even millions of times in a day. Generally, the server performs complex and time-consuming calculations whenever a browser requests a web page. It retrieves the latest posts, generates headers and footers, finds your site’s widget sidebar, and more. However, in many cases, the result of all these calculations is the same.

Wouldn’t it be nice if the server provided us with the final result instead of repeating this process for every request? This is precisely what happens in caching.

What Is Website Cache?

Website Cache means storing data temporarily for the user to use again in the future. So what exactly does a website cache do?

 When a user opens a website, the website cache collects all its data, converts it into an HTML file, and opens it in the user’s browser. If this is the first time the user enters the website, this process must be completed entirely; But if that website has enabled the cache feature, a copy of the website data will be stored in the cache the first time. In this case, from now on, every time a user enters the same website, the copy will be delivered to them.

In fact, in such a situation, there is no need to download and collect the website files from the beginning because the same copy has already been left. This feature removes a lot of overloads on the server; therefore, server performance will be faster.

Why Is Website Caching Important?

Websites are typically viewed hundreds or thousands or sometimes even millions of times a day. Needless to say, every time, the server has to perform relatively complex and time-consuming calculations to show the website to the user. By caching the website, the server no longer repeats these calculations and only remembers the final result and shows it to the users. This alone can dramatically increase page loading speed.

In other words, website caching reduces requests to the server; therefore, the website uses less bandwidth to display the page to the user. This is a massive plus for websites, especially those with limited resources. In addition to having a positive effect on user experience, website cache attracts the attention of search engines. Therefore, you can count on it to improve your website’s SEO.

How Does the Website Cache Work?

The cache system of the site works as follows: If someone goes to a website and requests information, the user’s browser requests the information from the server in the form of an HTTP Request. After processing the requested information, the server returns them to the browser in HTML files, and the user can view the website.

If a user has already requested this information, it will be stored in the cache, and the website’s loading speed will increase. If you modify cached content on your website, it may not be displayed to the user. In this case, you should clear the site cache in the settings of your website management panel.

Advantages of Caching

Using cache brings significant benefits to administrators and developers of mobile applications, websites, software, etc., some of which are as follows:

  1. Faster Load Times

Cache speed up the loading of webpages and applications by saving frequently used files and data. Applications and websites can speed up loading and operation by using the cached data, which is saved locally on your device or edge servers.

  1. Network Expenses Drop

By preserving the images and files that are required to access and use a firm’s website, caches can help a company lower its network costs. People can cut network traffic and save money by downloading and saving website text, images, and files to their cache instead of having to obtain them from the company’s network using their browsers. The website’s load time can be sped up by lowering such traffic, which can increase user satisfaction.

Disadvantages of Caching

While modern software relies heavily on the use of the cache, caches also have disadvantages:

  1. Caches can take up a lot of storage space

A cache is a small storage of files used by an application. But some caches may become very large and limit the free memory of your device. By clearing caches, you can delete files and reclaim the occupied memory of your device.

  1. A corrupted cache file causes the program to perform poorly

If one of the files stored in the cache memory has a problem, it causes the desired program to display the wrong information, to be disturbed, or to stop. Clearing caches is a common solution to fix programming problems, especially in browsers.

  1. Caches can prevent an application from loading the latest version of web pages or other data

In theory, apps are supposed to use caches only to display files that haven’t changed since the last visit and re-download files that have changed. But in practice, sometimes such a thing may not happen, and instead of re-downloading the modified file, the program loads the same cache file. In this case, the only way to view the latest version of a website or other data is to clear the cache. This way, the app is forced to download everything again.

What Are the Different Types of Caching?

  • Cache in DNS servers

DNS servers cache DNS records for faster lookups. When a domain name is searched on the Internet, the request is first sent to DNS cache servers to look up the IP address associated with the domain name. DNS caching can be done at various levels, including in the operating system, through ISPs and DNS servers, which speed up the operation of retrieving the IP address of a domain name.

  • Web Caching

Various web caching techniques can be implemented both on the server and user sides.

  1. Web cache on the server side:This type of storage uses a web proxy to keep the responses of the web server so that later, in this way, it can reduce the response delay.
  2. User-side web cache:This type of storage is based on the browser. To run websites faster, the web browser stores the HTML files, JavaScript, and images of the website the user has visited once in its cache memory.

Every time a user opens a web page, his browser has to download a lot of data (including JavaScript files, photos, videos, etc.) to display that page. Browsers cache such data to increase page loading speed and store a copy of the web page content on the hard disk of the user’s device. That way, the next time the user reloads the same web page, most of the content will load much faster without downloading it again.

Browsers keep these files until their time to live (TTL) expires, or the hard disk cache is full. (TTL indicates how long the content should remain cached.) Also, users can optionally clear their browser cache, which temporarily increases page load times. Because from now on, any web page reloaded will be as if it was the first time the user visited that page.

  • Cache in Content Distribution Network (CDN)

When your website traffic is worldwide, fast service with low latency will only be possible with proper infrastructure in different geographical locations. On the other hand, distributing the website infrastructure by yourself (as a website owner or administrator) is also not wise and cost-effective.

By providing a global network of edge servers (Edge Servers) to distribute a cached copy of website content, such as videos, web pages, images, etc., to users worldwide, CDN enables this service for you at the lowest cost.

Think of a CDN as a grocery store. Shoppers go to their neighborhood grocer instead of going to farms hundreds of miles away; It is true that they still have to walk a path to the shop, but it is much closer. Therefore, grocery shopping takes minutes instead of days. Similarly, a CDN stores website content (food) on its own servers (local stores) so that web pages load faster.

The content distribution network uses the edge server closest to the user to reduce the response time. CDN servers cache static data (data that does not need to be constantly changed). Since Web Assets are delivered to the user from the cache, the throughput increases dramatically.

What Is Cache Hit and Cache Miss?

A cache hit occurs when a file requested from the CDN edge server is responded to from its cache. For example, if the user intends to view a website using a CDN that includes a photo, the browser’s request to receive this photo reaches the CDN edge server. If the CDN has a copy of that photo in its cache, it will send it to the user; without sending the browser request to the main site server. In this case, a cache hit has occurred.

But if the CDN does not find the requested content in its cache, it sends the user’s request to the site’s main server; this is called a cache miss.

The more site content there is on the CDN edge servers, the better the user experience of viewing the site.

The cache hit ratio, as its name implies, is equal to the ratio of requests that the CDN can respond to using its cache to the total number of requests it receives. The total number of requests equals the number of cache hits and misses.

Frequently asked questions

  1. Does enabling website cache affect SEO?

Yes, the main benefit of website caching is to increase page loading speed. Since the speed of the website is one of the essential factors for search engines, activating the website cache is an important step to improve the SEO of the website.

  1. What are the best WordPress cache plugins?

There are many plugins to enable caching in WordPress websites, but these three plugins have worked best so far:

  • W3 Total Cache
  • WP Super Cache
  • Autoptimize
  1. What is stored in the web cache?

Caching allows the server to save the HTML file it creates in memory and use it as a reference the next time the server visits that website. As a result, the server is not required to create new HTML files for every website user. The website cache eventually fills out, which speeds up page loading times.

  1. How long does cached content stay on CDN servers?

When website servers respond to CDN, they send the requested content along with the corresponding TTL to tell the servers how long to store it. The TTL is stored in a part of the response called the “HTTP header” and specifies how many seconds, minutes, or hours the content should be stored. When the TTL expires, the CDN server cache removes that content.

  1. What is the difference between Cache and CDN?

The goal of CDNs, which are networks of proxy servers that are geographically dispersed, is to offer material to users more quickly. Information is cached when it is kept on a computer for a predetermined amount of time. While CDNs perform caching, not all caching is performed by CDNs, which is the primary distinction between CDNs and caching.


In this piece, we discussed what caching is and why it has grown in significance in computer science. At the same time, it’s important to not minimize the dangers and risks associated with caching. It takes time and experience to implement a properly defined caching system, so it’s not a simple operation. Understanding the most significant cache types is essential for creating the ideal system because of this. They can be condensed to a very small set, as was demonstrated. Every developer’s goal should be to master them all. In conclusion, caching is a necessary topic, and this article’s goal was to convey its fundamental ideas.