This week’s episode of Two Minute Tech Tuesday explains how the built-in Varnish Configuration Language (VCL) works. The built-in VCL is VCL code that is executed by default, even if you don't write any VCL yourself.

This week’s episode is about Grace mode, Varnish’s interpretation of stale-while-revalidate.

This week’s episode is about VCL — the Varnish Configuration Language — which is used to define your own caching policies in Varnish Cache and Varnish Enterprise, and the number one feature in Varnish.

If you've read a few of my blog posts, you probably already know I love the VCL (Varnish Configuration Language) idea, big time. Being able to change the processing logic via code opens a world of possibilities and makes pretty much all other tools feel constrained in their configurations. But...

But, well, VCL is code, and code is scary to a lot of users, and I can understand when you begin with Varnish and only have very limited configuration needs, VCL can feel complicated and some would prefer a simple, declarative language. The good news is that it's totally possible, let's see how we can help!