Caddy is a lightweight, general-purpose web server for Windows, Mac, Linux, BSD and Android. It is a capable alternative to other popular and easy to use web servers. (@caddyserver on Twitter)
The most notable features are HTTP/2, Let's Encrypt support, Virtual Hosts, TLS + SNI, and easy configuration with a Caddyfile. In development, you usually put one Caddyfile with each site. In production, Caddy serves HTTPS by default and manages all cryptographic assets for you.