What is Varnish Cache?
Varnish Cache is an open-source HTTP reverse proxy and caching accelerator designed to speed up content delivery by storing copies of web pages in memory and serving them directly without hitting the backend server.
How Does Varnish Cache Work?
Varnish sits in front of a web server and intercepts incoming HTTP requests. When a page is requested for the first time, Varnish fetches it from the backend server, stores a copy in RAM, and delivers it to the visitor. Subsequent requests for the same page are served directly from memory, dramatically reducing response times and server load.
Varnish uses a domain-specific configuration language called VCL (Varnish Configuration Language) that gives administrators fine-grained control over caching rules. It is widely used by high-traffic websites and content-heavy platforms to handle millions of requests per day. Varnish is particularly effective for content that does not change frequently, such as news articles, product pages, and blog posts.