What is Varnish?

Varnish Cache is a powerful web application accelerator, also known as a caching HTTP reverse proxy. It sits in front of web servers and caches frequently requested content in memory, dramatically improving website performance by reducing backend load and decreasing response times. Varnish can typically deliver cached content 300-1000x faster than retrieving it from the backend server.

Originally developed by Poul-Henning Kamp and later maintained by Varnish Software, Varnish is designed specifically for modern web architectures. It uses a unique approach with its Varnish Configuration Language (VCL), which gets compiled to C code for maximum performance. Major websites like The New York Times, The Guardian, and Facebook use Varnish to handle millions of requests per second with minimal hardware resources.

Varnish Performance Calculator