Do you mean libraries for backend languages, like Go and Java, or servers, like Nginx and Caddy? Because for Go there is the quic-go module[1], and since Caddy

Do you mean libraries for backend languages, like Go and Java, or servers, like Nginx and Caddy? Because for Go there is the quic-go module[1], and since Caddy is written in Go, it already has (experimental) support for HTTP/3[2]. [1]: https://github.com/lucas-clemente/quic-go https://github.com/lucas-clemente/quic-go [2]: https://caddyserver.com/docs/caddyfile/options#protocol https://caddyserver.com/docs/caddyfile/options#protocol