Varnish is a piece of software that, amongst other things, can make your website much faster. In a new post on his blog, Mattias Geniar tells you all about it.

Varnish can do a lot of things, but it's mostly known as a reverse HTTP proxy. It brands itself as an HTTP accelerator, making HTTP requests faster by caching them. ... Varnish is usually associated with performance, but it greatly increases your options to scale your infrastructure (load balancing, failover backends etc) and adds a security layer right out of the box: you can easily let Varnish protect you from the httpoxy vulnerability or slowloris type attacks.

https://ma.ttias.be/varnish-explained/

Be sure to watch Mattias' excellent talk he gave at this years Laracon: