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Cloudflare

/kloud-flair/noun

Filed underInfrastructureSecurity

In brief · quick answer

Cloudflare is a global network that provides CDN, DDoS protection, DNS, web security, and edge computing services. It sits between your website and its visitors, optimizing and protecting every request.

§ 1 Definition

Cloudflare runs one of the world's largest networks, operating in over 310 cities. It acts as a reverse proxy for your website, meaning all traffic passes through Cloudflare before reaching your server. This lets Cloudflare cache content (CDN), block malicious traffic (DDoS protection, WAF), optimize performance (image optimization, minification), and run code at the edge (Cloudflare Workers). It also provides authoritative DNS, SSL/TLS certificates, bot management, and analytics. Over 20% of all websites use Cloudflare, making it the most widely deployed edge network on the internet.

§ 2 How Cloudflare Works

You change your domain's nameservers to point to Cloudflare. This delegates DNS management to Cloudflare and routes traffic through its network. When a visitor requests your site, Cloudflare checks if it has a cached copy. If yes, it serves from the edge location nearest the visitor. If not, it fetches from your origin server while applying security filters, then caches and serves the response. This proxying is transparent to the visitor but gives you massive performance and security benefits.

§ 3 Key Services

CDN caches static and dynamic content at edge locations. DDoS Protection absorbs attacks up to terabit scale. WAF (Web Application Firewall) blocks SQL injection, XSS, and other threats. SSL/TLS provides free certificates and flexible encryption modes. Cloudflare Workers runs JavaScript/WebAssembly at the edge for custom logic. DNS offers blazing-fast resolution through the largest anycast network. Bot Management distinguishes humans from automated traffic.

§ 4 Cloudflare and Performance

Cloudflare's impact on performance goes beyond caching. It optimizes images on the fly (WebP conversion, resizing), minifies HTML/CSS/JavaScript, and uses HTTP/2 and HTTP/3 (QUIC) for faster connections. Argo Smart Routing finds the fastest path across the internet between Cloudflare and your origin server. The result is typically 40-60% faster page loads for visitors globally.

§ 5 Note

Cloudflare's free plan covers CDN, DDoS protection, SSL, and basic WAF for unlimited websites. Most small to medium sites never need to upgrade.

§ 6 In code

```javascript
// Cloudflare Worker: Add security headers
addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})

async function handleRequest(request) {
  const response = await fetch(request)
  const newHeaders = new Headers(response.headers)
  newHeaders.set('X-Content-Type-Options', 'nosniff')
  newHeaders.set('X-Frame-Options', 'DENY')
  newHeaders.set('Strict-Transport-Security', 'max-age=31536000')
  return new Response(response.body, {
    status: response.status,
    statusText: response.statusText,
    headers: newHeaders
  })
}
```

§ 7 Common questions

Q. Does Cloudflare slow down my site because it's an extra hop?: A. No. Cloudflare's network is engineered to be faster than direct connections. Caching, optimized routing, and protocol improvements more than compensate for the proxy hop.
Q. Is Cloudflare only for large sites?: A. Cloudflare's free tier is extremely generous and suitable for any site. Even personal blogs benefit from the CDN, SSL, and DDoS protection.

Key takeaways

Cloudflare is a reverse proxy network that provides CDN, DDoS protection, DNS, and edge computing.
Traffic routes through Cloudflare's global network before reaching your server.
Free tier covers CDN, SSL, and DDoS protection for unlimited sites.
Cloudflare Workers run custom code at the edge for near-zero-latency logic.

How Atomic Glue helps

We configure Cloudflare for clients to improve site speed, security, and reliability. From DNS setup to custom Workers, we handle the edge. Get in touch.

Get in touch

# Cloudflare

Category: Infrastructure (also: Security)

Author: Atomic Glue Editorial Team

## Definition

## How Cloudflare Works

You change your domain's [nameserver](/glossary/nameserver)s to point to Cloudflare. This delegates DNS management to Cloudflare and routes traffic through its network. When a visitor requests your site, Cloudflare checks if it has a cached copy. If yes, it serves from the edge location nearest the visitor. If not, it fetches from your origin server while applying security filters, then caches and serves the response. This proxying is transparent to the visitor but gives you massive performance and security benefits.

## Key Services

**CDN** caches static and dynamic content at edge locations. **DDoS Protection** absorbs attacks up to terabit scale. **WAF (Web Application Firewall)** blocks SQL injection, XSS, and other threats. **SSL/TLS** provides free certificates and flexible encryption modes. **Cloudflare Workers** runs JavaScript/WebAssembly at the edge for custom logic. **DNS** offers blazing-fast resolution through the largest anycast network. **Bot Management** distinguishes humans from automated traffic.

## Cloudflare and Performance

## Note

Cloudflare's free plan covers CDN, DDoS protection, SSL, and basic WAF for unlimited websites. Most small to medium sites never need to upgrade.

## In code

## Common questions
Q: Does Cloudflare slow down my site because it's an extra hop?
A: No. Cloudflare's network is engineered to be faster than direct connections. Caching, optimized routing, and protocol improvements more than compensate for the proxy hop.
Q: Is Cloudflare only for large sites?
A: Cloudflare's free tier is extremely generous and suitable for any site. Even personal blogs benefit from the CDN, SSL, and DDoS protection.

## Key takeaways

Cloudflare is a reverse proxy network that provides CDN, DDoS protection, DNS, and edge computing.
Traffic routes through Cloudflare's global network before reaching your server.
Free tier covers CDN, SSL, and DDoS protection for unlimited sites.
Cloudflare Workers run custom code at the edge for near-zero-latency logic.

## Related entries

Last updated July 2026. Permalink: atomicglue.co/glossary/cloudflare