This month's tip is more a theoretical exercise than anything else, just to show the power of VCL, and to explain a few regular expressions. I'm going to discuss VCL that deletes cookies.

Reusing connections between your Varnish instance and your backends (origins) is a good idea for multiple reasons. If your Varnish is on the same network as your backends and you're doing…

Moving to a new content delivery network (CDN) can seem daunting from an operational standpoint, and it’s important to ensure your CDN is set up correctly before you start migrating all your…

Varnish is an open source web accelerator that is designed for high-performance content delivery. Learn more about what Varnish is and how Fastly's varnish can help accelerate your content.

The cache hit ratio (or hit ratio for short) is the ratio of hits to cacheable requests (hits and misses combined). There's also cache coverage, the ratio of cacheable requests to all…

If you want to increase the efficiency of your Varnish (or Fastly) cache, you need to figure out what traffic is not cached. By definition, any traffic that reaches your origin is not cached…

In the continued quest to increase cache hit ratios, the chant is: "Normalize, normalize, normalize." Less variation in your requests means you have a higher chance of getting hits. This…

A long time ago, I was helping out at a gaming conference where there was an intranet CMS using a Twitter search plugin. Unfortunately, the rather saturated Internet connection was slowing…

Vary is one of the most powerful HTTP response headers. However, if used incorrectly, it can cause problems for developers. Understand vary header best practices to reduce mistakes and…

At Fastly, we’ve been steadily building the world’s most advanced CDN. Since our founding, we’ve expanded the public network to include 17 globally distributed points of presence (POPs) and…