VARNISH CACHE
The Cache Relied on by Millions of Sites
The free, open source software that enables super fast delivery of HTTP based content.
The Varnish Story
If you are not ready for Varnish Enterprise yet, don't worry! Start with Varnish Cache like millions of other developers have. Varnish Cache is a popular open-source web application accelerator.
The Varnish story begins in 2005. The online newspaper Verdens Gang was growing in popularity and with over 45 million page views per week needed a better way to handle traffic. Believing there was a way to reduce server numbers while speeding up page load times, a team drafted an open source solution to VG’s problem. After securing funding, the Varnish Cache project began.
Varnish Cache
Varnish Goes Viral
Varnish Cache succeeded beyond expectations. It lowered average page loads from 150 ms to under 30 ms, while reducing backend server needs by 400%!
It was so effective that other newspapers took notice, and the Varnish code was open-sourced to share these benefits. Adoption grew over the years, and now millions of websites rely on Varnish Cache to accelerate HTTP delivery.
Web Caching
How Varnish Works
Varnish is an HTTP reverse proxy that works by caching frequently requested web pages, so they can be loaded quickly without having to wait for a server response.
When a user requests a particular webpage, Varnish checks to see if the page is already in cache. If it is, Varnish serves the content directly, which saves a lot of time compared with sending requests to the origin server.
Why Varnish is Different
There are a few design decisions that, from the beginning, set Varnish Cache apart from the competition. These technical features all stem from the philosophy that Varnish should be fundamentally fast, and built from the ground up with performance in mind.
Built for HTTP
Other accelerators began as client-side caches or origin servers. Varnish's HTTP focus means much faster page loads.
Heavily Threaded
Each client connection is handled by a separate worker thread to maximize performance.
Data Storage in Virtual Memory
The OS decides what is stored in memory and what gets paged out to disk.
Log Data Stored in Shared Memory
To minimize the number of system calls in the fast path.
Varnish Configuration Language
The Key to Customization
Key to Varnish Cache is the flexibility of Varnish Configuration Language, or VCL.
From a command-line interface, VCL lets you write policies and control every aspect of the request and response process. With VCL handling decision making, Varnish is more adaptable than other HTTP accelerators.
VCL is also super-fast and configures without restarting because it gets transpiled to C, compiled to a shared object, and loaded directly into Varnish.
NEW! Varnish Cache Support
Exciting news from Varnish Software: we're thrilled to introduce official support for Varnish Cache!
As the primary stewards of the Varnish Cache project and trusted providers of Varnish Enterprise, we're extending our expert support to Varnish Cache users worldwide. Our support team includes Varnish Core Engineers and represents the greatest concentration of Varnish expertise in the world.
Varnish Cache or Varnish Enterprise?
As popular as Varnish Cache is, when it came to emerging use cases and mission-critical HTTP challenges, something more was needed.
Varnish Enterprise has filled this need, with more features, more performance and support for video streaming, app delivery and more.
Cache and Enterprise are built from the same core principles but for different priorities.
Free, Open Source Software
Get Varnish Cache
If you think your business could benefit from expert support and extensive features, custom-fit to unique needs, then Varnish Enterprise is the software for you.
If you've got the know-how and motivation to dive into the open-source project, you’ll be delighted with Varnish Cache.
Varnish Cache is free software licensed under a two-clause BSD, or FreeBSD license.
Download Varnish Cache | View Documentation
The Varnish Book
Varnish 6 by Example
Varnish 6 by Example is the essential guide to all things Varnish 6, with tutorials for features and modules across Varnish Cache and Varnish Enterprise.
It’s a practical book full of tips and best practices for getting the most out of your Varnish setup and reaching new heights in your caching operations, whether you’re new to Varnish or an experienced pro.
Fully updated to cover the latest features, modules and use cases, Varnish 6 By Example provides everything you need to learn VCL, scale web operations, build custom CDNs and level-up your Varnish skills.
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We’re happy to help with any questions you may have about our software, support, pricing or anything else Varnish related. We can assist you in finding the solution that best fits your needs and set up trials too.
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