A Content Delivery Network puts your content closer to users worldwide. Proper CDN configuration dramatically reduces latency and improves user experience.
How CDNs Work#
Without CDN:
User (Tokyo) → Origin Server (New York)
Latency: ~200ms
With CDN:
User (Tokyo) → Edge Server (Tokyo) → Origin Server (New York)
↑
(Only on cache miss)
Latency: ~20ms (cache hit)
What to Cache#
Static Assets (Long TTL):
✓ JavaScript bundles
✓ CSS files
✓ Images
✓ Fonts
✓ Videos
Dynamic Content (Short/No TTL):
✓ HTML pages (with care)
✓ API responses (selective)
✓ User-specific content
Never Cache:
✗ Authentication tokens
✗ Payment information
✗ Personal data
✗ Real-time data
Cache Headers#
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Versioned Assets#
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CDN Configuration (Cloudflare)#
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Cache Invalidation#
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Edge Computing#
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Image Optimization#
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Monitoring#
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Multi-CDN Strategy#
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Best Practices#
DO:
✓ Version static assets with content hashes
✓ Set appropriate Cache-Control headers
✓ Use cache tags for targeted invalidation
✓ Monitor cache hit rates
✓ Compress responses (gzip/brotli)
✓ Use HTTP/2 or HTTP/3
DON'T:
✗ Cache user-specific content publicly
✗ Set overly long TTLs for dynamic content
✗ Forget to invalidate after deployments
✗ Cache error responses
✗ Ignore Vary headers
Conclusion#
CDNs are essential for global performance. Start with static asset caching, carefully implement dynamic content caching, and monitor your cache hit rates.
The goal is to serve as much as possible from the edge—closer to your users.