How to Set Up Nginx HTTP/3 with Cloudflare in 2026

HTTP/3 over QUIC is now production-ready in 2026. This guide configures end-to-end HTTP/3 with Cloudflare handling public traffic and Nginx on the origin.

Step 1 — Install Nginx with HTTP/3 Support

add-apt-repository ppa:ondrej/nginx-mainline -y
apt update && apt install nginx -y
nginx -V 2>&1 | grep http_v3

Step 2 — Configure Nginx for HTTP/3

server {
    listen 443 quic reuseport;
    listen 443 ssl;
    http2 on;
    http3 on;
    http3_hq on;

    add_header Alt-Svc 'h3=":443"; ma=86400';

    ssl_certificate /etc/letsencrypt/live/domain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/domain.com/privkey.pem;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_early_data on;
}

Step 3 — Open UDP Port 443

ufw allow 443/udp
ufw reload

Step 4 — Enable HTTP/3 in Cloudflare

Cloudflare Dashboard → Speed → Optimization → Protocol Optimization → HTTP/3 (with QUIC) → ON

Step 5 — Verify

curl --http3 -I https://yourdomain.com

Conclusion

HTTP/3 reduces page load times by 15-30% especially on mobile. Our team configures Nginx performance optimisation including HTTP/3.