Router is the Flynn HTTP/TCP cluster router. It relies on service discovery to keep track of what backends are up and acts as a standard reverse proxy with random load balancing. HTTP domains and TCP ports are provisioned via a HTTP API. Only two pieces of data are required: the domain name and the service name. etcd is used as a pluggable persistence backend so that all instances of router get the same configuration.
The primary benefits are that it uses service discovery natively and supports dynamic configuration. Both HAProxy and nginx require a new process to be spawned to change the majority of their configuration.