Use HTTP/2: Faster, Multiplexed Connections

HTTP/2 is one of the biggest performance upgrades that requires zero code changes. If your server still speaks HTTP/1.1, you're leaving massive speed gains on the table.

HTTP/1.1 vs HTTP/2

Feature	HTTP/1.1	HTTP/2
Connections per domain	6 max	1 (multiplexed)
Header compression	None	HPACK compression
Request prioritization	None	Stream priorities
Server push	None	Supported
Binary protocol	No (text)	Yes (faster parsing)

The Waterfall Problem

With HTTP/1.1, the browser can only make 6 requests at a time to one domain:

HTTP/1.1 (6 connections):
[js-1]  [css-1]  [img-1]  [img-2]  [img-3]  [img-4]
                                                        [img-5]  [img-6]  [font-1]  [img-7]

HTTP/2 (1 multiplexed connection):
[js-1]  [css-1]  [img-1]  [img-2]  [img-3]  [img-4]  [img-5]  [img-6]  [font-1]  [img-7]
(all download simultaneously)

How to Enable HTTP/2

Check Current Protocol

# Check from command line
curl --http2 -I https://yoursite.com 2>&1 | head -5

# If you see "HTTP/2 200", you're good
# If you see "HTTP/1.1 200", you need to upgrade

Nginx

# Enable HTTP/2 — just add 'http2' to the listen directive
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;

    ssl_certificate /etc/ssl/certs/yoursite.crt;
    ssl_certificate_key /etc/ssl/private/yoursite.key;

    # Enable HTTP/2 push for critical resources (optional)
    http2_push /styles/critical.css;
    http2_push /fonts/brand.woff2;
}

Apache

# Requires mod_http2
# In httpd.conf or virtual host config
Protocols h2 h2c http/1.1

<VirtualHost *:443>
    Protocols h2 http/1.1
    SSLEngine on
    SSLCertificateFile /etc/ssl/certs/yoursite.crt
    SSLCertificateKeyFile /etc/ssl/private/yoursite.key
</VirtualHost>

CDN Providers (Automatic)

Most CDN providers support HTTP/2 out of the box:

Provider	HTTP/2	HTTP/3	Notes
Cloudflare	✅ Auto	✅ Auto	Free tier included
Vercel	✅ Auto	✅ Auto	No config needed
Netlify	✅ Auto	❌	Automatic
AWS CloudFront	✅ Auto	✅ Optional	Enable in distribution settings
Fastly	✅ Auto	✅ Auto	Automatic

If you're using a CDN, HTTP/2 is likely already enabled.

Node.js (Express)

import { createSecureServer } from "http2";
import { readFileSync } from "fs";
import express from "express";

const app = express();

const server = createSecureServer({
  key: readFileSync("./key.pem"),
  cert: readFileSync("./cert.pem"),
  allowHTTP1: true, // Fallback for old clients
}, app);

server.listen(443);

HTTP/1.1 Hacks You Can Remove

Some old optimization techniques are counterproductive with HTTP/2:

Domain Sharding — Remove It

<!-- ❌ HTTP/1.1 trick — splits requests across domains -->
<img src="https://img1.example.com/photo-1.jpg">
<img src="https://img2.example.com/photo-2.jpg">
<img src="https://img3.example.com/photo-3.jpg">

<!-- ✅ HTTP/2 — use one domain, multiplex everything -->
<img src="https://cdn.example.com/photo-1.jpg">
<img src="https://cdn.example.com/photo-2.jpg">
<img src="https://cdn.example.com/photo-3.jpg">

Sprite Sheets — Split Them

/* ❌ HTTP/1.1 trick — combined all icons into one image */
.icon-home { background: url(sprites.png) -10px -20px; }
.icon-user { background: url(sprites.png) -40px -20px; }

/* ✅ HTTP/2 — individual files load in parallel */
.icon-home { background: url(icons/home.svg); }
.icon-user { background: url(icons/user.svg); }

File Concatenation — Let the Bundler Decide

With HTTP/1.1, combining files reduced requests. With HTTP/2, smaller files enable better caching (change one module, only that file is re-downloaded).

HTTP/3 (QUIC)

HTTP/3 uses QUIC (UDP-based) instead of TCP:

• Faster connection setup — 0-RTT resumption
• No head-of-line blocking — packet loss on one stream doesn't block others
• Better on mobile — handles network switching (Wi-Fi ↔ cellular) gracefully

Most CDN providers now support HTTP/3 automatically.

Verifying HTTP/2

Browser DevTools

1. Open Network tab
2. Right-click column headers → enable Protocol
3. Look for h2 (HTTP/2) or h3 (HTTP/3)

Online Tools

• HTTP/2 Test
• SSL Labs — shows protocol support

Quick Wins Checklist

• Check current protocol: curl --http2 -I https://yoursite.com
• Enable HTTP/2 on your server (Nginx: listen 443 ssl http2)
• Or use a CDN that supports HTTP/2 automatically
• Remove domain sharding if you were using it
• Ensure HTTPS is enabled (required for HTTP/2 in browsers)
• Consider HTTP/3 via CDN providers that support it
• Remove unnecessary file concatenation / sprite sheets