Thursday, June 20News That Matters

What is the Process Flow for Varnish Caching?


With the proliferation of the internet and the rise in digital dominance, creating an online presence and developing a website is a must for all business organization. Each and everything organization today plans to embed a website for their business, and when done, they flood the internet with thousands of sites. Given that there are a plethora of choices available for the users, it is desirable that your website loads faster and offers excellent speed. Though there are different ways of achieving the above, caching is a method used by most of the website owners.

What is Caching and its types?

Caching is a process that stores content in a temporary location. The next time a request is put up for accessing the same content, it can be routed through the cache itself. There are four different kinds of caching

  1. Data
  2. Web
  3. Application
  4. Distributed

The sole purpose behind the inception of caching is to accelerate the speed at which requests are answered, in a way enhancing the overall user experience.

How does Varnish Caching work?

Every time a user browses the website or visits a page, an HTTP call is made by the front end, and then, your Cloud Server Hosting would respond, accordingly. In case you have a small-scale organization, these might not matter much. But once, the website scales in terms of the user and traffic, numerous requests sent to the server at the same, tend to affect the page performance.

This is where we ideate the adoption of a technique, namely Varnish caching. Varnish Cache is also known as the web application accelerator. It is regarded as the HTTP reverse proxy and acts as the middle man between the user and the server.

This suggests that every request initiated by the user are first sent to the Varnish Cache and then, sent to the server to respond in the appropriate way.

Example: Let me explain it in a better way.

Suppose a user makes a request to access a particular page of the website. This is first received by the Varnish and then sent it to the server. As Varnish acts as the gateway between the user and the client, the response by the server is also sent first to Varnish. Here, the response is cached by Varnish, before forwarding it to the concerned user.

Now, the next time when a request for similar content is received by the Varnish, the response is given by the same. This prevents the possibility where the web server is flooded with numerous requests, ones that the server has answered previously.

Now, the web server can adhere to a greater number of requests given the same time but at a better speed. Hence, the overall performance of the website increases.


Get /web-page-request (client) —→ Varnish-

Cache –→ Get /web-page-response (Server) —-→ Varnish-Cache –→ Back to client.

The internal functioning of Varnish can be changed or modified by editing the Varnish Configuration Language. The admin can add logic within the same to manipulate the response and request between the user and the server.

Final Word

Whatever be the kind of business or website you host, introducing Varnish Cache is one of the easiest ways to web traffic and optimize the speed and performance of the site.

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