Traefik is an open source reverse proxy and load balancer. Originally, these two features were handled by different components:

• Reverse proxies were implemented in HTTP servers such as Apache and NGINX
• Load balancers were implemented in dedicated products, whether software- or hardware-based

But quite recently, several open source projects emerged that implement both features in software. Traefik is one of these tools, and it leverages several new technologies:

• It is implemented in the Go language, a compiled language that offers high performance and ease of development
• It is highly integrated with the Docker ecosystem
• It has built-in support for Let's Encrypt, a free TLS certificate authority

Before looking at how to use Traefik, let's first explain what a reverse proxy is, what a load balancer is, and why these two components are of great importance when deploying web applications or microservices.