When you type a web address into your browser and request a web page, it triggers a series of steps. Your browser sends a query to a server, that server returns the property, and the browser finishes responding. However, this is only a superficial overview; A lot more happens under the hood.
One of the many technologies that web servers use to serve content faster is Varnish Cache, a reverse caching proxy. Many traditional and VPS hosting providers use Varnish as part of their technology stack, making it an important part of modern web infrastructure.
What is Varnish Cache?
Varnish Cache is an open-source web application accelerator that helps optimize web pages for faster loading times. It does this by storing copies of web pages in memory. When a user requests a webpage, they get back a cached version rather than waiting for the origin web server to generate the page from scratch.
This reduces server load and shortens page load times, making websites more responsive and improving user experience. Varnish lets you control how it stores pages in its cache using the HTTP Cache Control header. Using these, you can specify when the cached version of a page should expire before Varnish returns it to the origin server to regenerate.
This gives you more control over the performance of your website and allows you to fine-tune it even further for optimal results. Because it is open-source and relatively easy to use, millions of websites on the web now take advantage of the Varnish cache to improve performance.
Origin of the Varnish Cache open-source project
The Varnish Cash open-source project was originally launched in 2006 by the Norwegian tabloid, the digital arm of the Vardens gang. Poul-Henning Kamp, a popular developer who enthusiastically supported the FreeBSD project, served as an independent consultant during its development.
Realizing its potential, the developers formed an entirely new company, Varnish Software, to oversee development. In 2008, it released Varnish 2.0, with progressive new iterations being released since then. Varnish 7.1 comes out in March 2022.
how varnish cache works
It is important to understand that the Varnish cache is just one of many elements that combine to improve server speed. At its core, Varnish works by caching the most frequently requested pages on your website, so they can be loaded quickly without waiting for a server response.
When a user requests a page from your website, Varnish checks to see if it already has the page in its cache. It uses the Varnish configuration language to create critical points that handle each HTTP request sent to the server.
If Varnish finds a cached version of a page, it serves it directly instead of sending another request to the origin server. This saves time as there is no need to wait for a response while the content is being delivered from the server’s cache.
Additionally, since cached pages do not require any processing from the backend server, Varnish can deliver them more quickly than non-cached pages. Varnish also enables you to customize how and when it delivers content based on various parameters such as device type or geographic location.
By doing so, you can ensure that you are providing the most optimized version of your content to your users, which further improves performance and reduces load times. Popular hosting providers like Siteground and Bluehost use Varnish to improve speed.
Now, once the page is cached, Varnish will serve it instead of the request going directly to your server.
Nginx and Varnish work perfectly together
Using the Varnish cache is a simple, yet effective way of improving speed. Varnish also integrates well with other software like Nginx.
Nginx is popular, open-source, web-serving software used by many high-demand sites to improve load balancing and ensure smooth media streaming. If you are installing Varnish on your server, consider adding Nginx to improve content and application delivery.