How it works

Varnish Software’s content delivery solutions are built on top of Varnish, a uniquely powerful caching technology.

Many of the world’s biggest and most popular brands rely on Varnish for delivering digital content at optimal speed and scalability.

Using Varnish solutions you can take back control of how, when, where and to whom you deliver your digital content while reducing traffic load on the backend.

Origin Server
Putting a proxy in front of your origin servers protects the backend from flooding and lets the cache do the heavy lifting.
Varnish Server
Caching with Varnish enables 300% to 1000% faster content delivery, and reduces backend server load by up to 89% while handling unlimited simultaneous visitors.
Varnish ensures speedy, responsive content delivery optimized by device type. Serving content quickly and efficiently doesn’t just mean you can serve more users, it also gives them faster downloads and a better experience.

Web App Performance

As a caching layer that sits between origin servers and website visitors, Varnish Enterprise decreases page load times significantly and ensures high-performance HTTP and API content delivery. It scales easily to match any demand and helps websites stay online and responsive, even when delivering personalized and complex, dynamic content. 

Learn what Varnish API and Web Acceleration can do.

Origin Server
Let your origin do what it’s good at: ingesting, mix and packaging, while Varnish does the heavy lifting, as it’s compatible with all the major video formats (HLS, HSS, HDS, etc.).
Varnish Server
Thanks to MSE, Varnish can store huge volumes of video as origin shield, making sure requests go to the origin only when absolutely necessary.
Cloud Server
Place the video caching edge close to your user, be it live, VoD or catch-up to ensure minimal startup time for your customer.
Varnish ensures speedy, responsive content delivery optimized by device type. Serving content quickly and efficiently doesn’t just mean you can serve more users, it also gives them faster downloads and a better experience.

Video Streaming

Sitting between viewers, CDNs and backend infrastructure, Varnish Enterprise can deliver seamless live, OTT and VoD streaming at scale. It provides highly optimized video delivery while protecting critical infrastructure, handling demand while delivering the high-performance, responsive video streaming experiences that viewers demand.

Learn what Varnish Enterprise can do.

Origin Server
Deploying origin servers in multiple locations may cause a lot of headaches because of replication and synchronization. With Varnish you can reach customers all over the world without multiplying your origins.
Varnish Server
As the brain of your setup, your origin needs to be accessible globally by the edge server, and it must be protected from abuse.
Varnish is easy and quick to deploy, hence it can easily be deployed anywhere in the world. In the cloud, virtualized, containerized or on bare metal, put Varnish close to your user to reduce latency.

Content Delivery

A fully customizable edge caching and origin protection technology stack, Varnish Enterprise helps content providers build in-house private CDNs, hybrid CDNs, consumer CDNs, and advanced edge platforms. Varnish Enterprise can reach uncharted levels of performance while mitigating cost escalation to provide true ROI.

Learn what Varnish Enterprise can do.

Does it work with…

Compatibility is key. Varnish is architecture-agnostic, caching virtually any kind of content and supporting the world’s most-used web technologies. Read up on a few of the most common CMSes, e-commerce platforms, CDNs and others that Varnish supports:

Serious About Security

Staying ahead of security threats is a tough job, but one we’re committed to. We’re always working to stay ahead of the next major security issue and keep you protected.

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Securely encrypt all cached data using dual-key AES 256 encryption, giving each cached object its own unique key. Using this solution you can ensure any leaked or hacked data is rendered inaccessible.

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Traffic Inspection

Inspect HTTP traffic and detect malicious requests at the edge before they reach your web application.

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HTTPS Support

SSL/TLS (HTTPS) encryption is, by now, a requirement for security, privacy and even SEO. The General Data Protection Regulation (GDPR) also highly recommends encryption of data wherever possible. With Varnish, you can protect your client-side and backend.

Under The Hood

Varnish Configuration Language (VCL) is Varnish's built-in language for controlling HTTP request handling, routing, caching, and more. Varnish modules (VMODs) are also a modular way to customize your Varnish setup. So what do VCL and VMODs look like in action?



This VCL snippet strips all the cookies that should not be kept.

We want to keep certain cookies if the req.url matches a specific condition, otherwise we will just remove all the other cookie headers.


Pre-fetch with vmod-http

Here we use a combination of vmod_kvstore (key value storage) and vmod_http (external requests).

Using these together we can prefetch content in a live streaming scenario and pace the background fetches triggered by vmod_http.

We use a “counter” function to make sure a single URL per second can trigger a prefetch request. This is to avoid overwhelming our backends. Without that counter we would push 10,000 prefetch requests to the backend.



For each incoming request we buffer the request body and try to parse it, assuming it is in JSON format.

If it is in JSON format, we extrapolate the value associated to the key “authorization”.
This is a good way to run a check on your request bodies and extend your authorization control.



Vmod-rewrite does Apache-style rewrite rules. It aims to reduce the amount of VCL to be written when many rewrites or manipulations need to be applied to URLs or headers.

A path to a file containing the rules must be specified and these will be applied at run time to every incoming request.

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