Caddy is an open-source, fast, cross-platform web server written in Go, best known for its automatic HTTPS features. It is designed to be simple, easy to use, and secure. Caddy 2.6 has enabled HTTP/3 by default, virtualizes the file system, and increases the performance of static files and FastCGI.

Source: LXer – Caddy 2.6 Web Server Brings HTTP/3 Support by Default