HTTP/3 is one of the easiest upgrades you can make for faster web delivery. In this guide, we’ll show you how to enable HTTP/3 step by step in LiteSpeed Web Server. You’ll also learn what HTTP/3 is, why it’s important for optimization, and how to check if it’s working.
What Is LiteSpeed
LiteSpeed is a high-performance web server built for speed and efficiency. It stays lightweight yet remains compatible with Apache configurations. Because of that, many admins use it for WordPress, eCommerce projects, and other high-traffic sites. In addition, LiteSpeed includes advanced caching and built-in SSL support, which makes it a strong fit for modern web apps.
What Is HTTP/3 and the QUIC Protocol
HTTP/3 is the newest version of the web’s main protocol. Instead of running on TCP like older versions, it runs on QUIC, which uses UDP. TCP is reliable, but it adds overhead because it checks and confirms packets in a strict sequence. UDP works differently since it is faster and better suited for real-time delivery. That design makes QUIC a smart match for modern websites that need speed and responsiveness.
When Should You Use HTTP/3
HTTP/3 is most useful when your site serves mobile users or international visitors. It also helps when your application depends on real-time interaction, since it handles modern connection behavior more smoothly. Because page speed impacts user experience, HTTP/3 can also support SEO goals through faster loading and more stable performance.
What You Need Before You Start
Before you change any LiteSpeed settings, make sure your setup meets three requirements.
- You need LiteSpeed version 5.4 or newer.
- You must have UDP port 443 open, since QUIC traffic uses UDP.
- You need a valid SSL certificate, because HTTP/3 only works over HTTPS.
Once these pieces are in place, the actual setup inside LiteSpeed only takes a few minutes.
How to Enable HTTP/3 in LiteSpeed
Start by logging into the LiteSpeed WebAdmin panel in your browser. You can reach it with:
https://your-ip:7080 After you log in, go to Configuration → Server → SSL. In this section, set Enable QUIC to Yes, and then set Enable HTTP/3 to Yes as well. Once you save the changes, click Graceful Restart so LiteSpeed reloads the configuration without unnecessary disruption.
Update Your Firewall for UDP 443
Even if HTTPS already works, HTTP/3 will fail if UDP 443 is blocked. Since QUIC uses UDP, you need to allow that traffic through your firewall. If you use firewalld, you can run:
sudo firewall-cmd --permanent --add-port=443/udp
sudo firewall-cmd --reload After that, your server can accept HTTP/3 connections properly.
Test If HTTP/3 Is Working
Once LiteSpeed and your firewall are updated, you should confirm that HTTP/3 is active. You can test with an online tool like http3check.net, which shows whether your site negotiates HTTP/3. If you prefer the terminal, you can also run:
curl -I --http3 https://yourdomain.com If the response confirms HTTP/3, your setup is complete.
Optional Per-Domain Settings
If you only want HTTP/3 enabled for a single site, LiteSpeed also supports per-domain configuration. In that case, go to Configuration → Virtual Hosts → YourDomain → SSL, and enable the same HTTP/3 settings there. This approach is helpful when you host multiple projects and want tighter control.
Watch Our YouTube Video on HTTP/3 in LiteSpeed Web Server
If you prefer a visual walkthrough, check out the connected YouTube video for this guide.
Final Thoughts
Enabling HTTP/3 and QUIC in LiteSpeed is a quick change that can improve speed and reliability, especially for mobile traffic, real-time apps, and global visitors. Once you enable it in WebAdmin, open UDP 443, and confirm it with a test, your server is ready for modern web delivery.