nginx http3

server {
    listen 443 ssl;              # TCP listener for HTTP/1.1
    listen 443 http3 reuseport;  # UDP listener for QUIC+HTTP/3

    ssl_protocols       TLSv1.3; # QUIC requires TLS 1.3
    ssl_certificate     ssl/www.example.com.crt;
    ssl_certificate_key ssl/www.example.com.key;

    add_header Alt-Svc 'h3=":443"';   # Advertise that HTTP/3 is available
    add_header QUIC-Status $quic;     # Sent when QUIC was used
}

Introducing a Technology Preview of NGINX Support for QUIC and HTTP/3 - NGINX

We are pleased to announce the technology preview of QUIC+HTTP/3 for NGINX at a special open source repository. This is pre‑release software, based on the IETF QUIC draft and is maintained in a development branch, isolated from the stable and mainline branches.

https://www.nginx.com/blog/introducing-technology-preview-nginx-support-for-quic-http-3/