Introduction
The factors affecting website speed are not just server power, cache, or CDN. The internet protocol used also directly affects performance.
The new technology that has come to the fore in recent years:
HTTP/3
So what is HTTP/3? How does it differ from HTTP/2? What do you lose if your hosting provider doesn't support it?
In this article we will explain this in a technical yet accessible way.
1. What Is HTTP? A Brief Primer
It is the communication protocol between the browser and the server.
| Protocol | Year | Feature |
|---|---|---|
| HTTP/1.1 | 1997 | Old, slow |
| HTTP/2 | 2015 | Multiplexing |
| HTTP/3 | 2022 | QUIC (UDP-based) |
The goal of every new version:
- Less latency
- Faster connections
- More stable data transfer
2. Why Was HTTP/1.1 Slow?
The problem with HTTP/1.1:
A separate connection is required for every file
When a page loads:
- HTML
- CSS
- JS
- Images
- Fonts
The browser can open only a limited number of connections at the same time.
This results in:
Queue β Waiting β Slow loading
3. What Did HTTP/2 Introduce?
The biggest innovation brought by HTTP/2:
Multiplexing (multiple data streams over a single connection)
That is:
- A single TCP connection
- Multiple files at the same time
But there was still one problem:
TCP Head-of-Line Blocking
Meaning: if one packet is lost, the entire connection waits.
4. What Did HTTP/3 Change?
HTTP/3 uses UDP instead of TCP and operates with the QUIC protocol.
| Feature | HTTP/2 | HTTP/3 |
|---|---|---|
| Protocol | TCP | UDP |
| Connection setup | Slow | Fast |
| Packet loss | Entire connection waits | Only that packet is affected |
| Mobile performance | Average | Excellent |
| Latency | Low | Even lower |
The most important difference:
Packet loss does not slow down the site
This makes a huge difference especially for mobile users.
5. Why Is HTTP/3 Faster?
1. Faster TLS Handshake
HTTP/2:
TCP + TLS = 2β3 round trips
HTTP/3:
QUIC = 1 round trip
This makes a particular difference with distant servers.
2. No Head-of-Line Blocking
HTTP/2:
1 packet lost β all data waits
HTTP/3:
1 packet lost β only that packet is retransmitted
3. Connection Migration
Very important for mobile users:
Example:
- WiFi β 4G switch
- IP address changes
HTTP/2:
Connection drops β reconnect
HTTP/3:
Connection continues
This significantly affects real-world performance.
6. How Much Speed Difference Does HTTP/3 Make?
Real-world averages:
| Protocol | TTFB | Page Load |
|---|---|---|
| HTTP/1.1 | 600 ms | 3.5 s |
| HTTP/2 | 300 ms | 2.2 s |
| HTTP/3 | 220 ms | 1.8 s |
Especially if:
- You use a CDN
- You have global visitors
- Mobile traffic is high
HTTP/3 makes a significant difference.
7. Is HTTP/3 Always Faster?
No. If:
- The user is very close to the server
- Latency is already very low
- There is no packet loss
The difference between HTTP/2 and HTTP/3 can be minimal.
HTTP/3 makes the biggest difference in these situations:
- Mobile users
- Traffic from distant countries
- Unstable internet connections
- High latency
8. How to Test HTTP/3
You can test via the terminal:
curl -I --http3 https://site.com
Alternatively:
- Chrome DevTools β Network β Protocol column
- If it says HTTP/3, it is active
9. How Is HTTP/3 Activated?
It can be activated at 3 layers:
| Layer | HTTP/3 |
|---|---|
| Server | Yes |
| CDN | Yes |
| Load Balancer | Yes |
The easiest method:
HTTP/3 via CDN
Because most hosting providers do not yet offer full support, but CDNs do.
10. Server Software That Supports HTTP/3
| Server | HTTP/3 |
|---|---|
| LiteSpeed | Available |
| Nginx | Available (recent versions) |
| Apache | Limited |
| CDN services | Available |
11. HTTP/3 and Core Web Vitals
HTTP/3 affects the following metrics:
| Metric | Impact |
|---|---|
| TTFB | Lower |
| LCP | Faster |
| FCP | Faster |
| CLS | No impact |
It particularly affects TTFB and LCP. This can indirectly affect SEO performance.
12. Should You Use HTTP/3?
| Site Type | HTTP/3 |
|---|---|
| Small blog | Not essential |
| Corporate site | Recommended |
| E-commerce | Recommended |
| Global traffic | Definitely required |
| High mobile traffic | Definitely required |
13. Summary
| Technology | Impact |
|---|---|
| HTTP/1.1 | Slow |
| HTTP/2 | Fast |
| HTTP/3 | Faster |
| HTTP/3 + CDN | Fastest |
CONCLUSION
Site speed is not determined by server power alone.
These factors work together:
Server + Cache + CDN + HTTP/3 = Maximum performance
HTTP/3 delivers significant performance gains especially for:
- Mobile users
- Remote locations
- High-latency connections