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.

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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

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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 → Waiting → Slow loading

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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.

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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.

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5. Why Is HTTP/3 Faster?

1. Faster TLS Handshake

HTTP/2:

TCP + TLS = 2–3 round trips

HTTP/3:

QUIC = 1 round trip

This makes a particular difference with distant servers.

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2. No Head-of-Line Blocking

HTTP/2:

1 packet lost → all data waits

HTTP/3:

1 packet lost → only that packet is retransmitted

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3. Connection Migration

Very important for mobile users:

Example:

• WiFi → 4G switch
• IP address changes

HTTP/2:

Connection drops → reconnect

HTTP/3:

Connection continues

This significantly affects real-world performance.

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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.

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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

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8. How to Test HTTP/3

You can test via the terminal:

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

Alternatively:

• Chrome DevTools → Network → Protocol column
• If it says HTTP/3, it is active

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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.

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10. Server Software That Supports HTTP/3

Server	HTTP/3
LiteSpeed	Available
Nginx	Available (recent versions)
Apache	Limited
CDN services	Available

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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.

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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

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13. Summary

Technology	Impact
HTTP/1.1	Slow
HTTP/2	Fast
HTTP/3	Faster
HTTP/3 + CDN	Fastest

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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

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