Edge Caching vs CDN: Which Should You Choose in 2025?

The line between CDNs and edge caching has blurred significantly. Traditional CDNs now offer compute capabilities, while edge caching solutions provide global distribution. This guide helps you choose the right approach for your specific needs.

Understanding the Difference

When to Use a Traditional CDN

CDNs excel at serving static assets globally:

• Static websites: HTML, CSS, JavaScript, images
• Media streaming: Video, audio files
• Software downloads: Installers, updates
• Simple caching rules: Cache everything with fixed TTL

CDN Limitations

• Limited dynamic content support
• Basic cache key options
• No custom logic execution
• Simple invalidation only

When to Use Edge Caching

Edge caching is essential for dynamic, personalized content:

• API responses: Cache GET requests intelligently
• Personalized content: User-specific but cacheable data
• Real-time data: Stock prices, sports scores with short TTL
• A/B testing: Serve variants at the edge
• Authentication: Validate tokens without origin round-trip

Edge Caching Advantages

• Custom cache logic per request
• ML-powered TTL optimization
• Compute at 200+ global locations
• Sub-20ms response times globally

Feature Comparison

The Hybrid Approach

Most production systems use both:

1. CDN layer: Cache static assets (images, CSS, JS)
2. Edge caching layer: Cache API responses intelligently
3. Origin: Handle cache misses and writes

This layered approach maximizes cache hit rates while keeping infrastructure simple.

Cost Considerations

CDNs are cheaper for static content, but edge caching provides better ROI for dynamic content:

• CDN: Pay per GB transferred, cheap for static files
• Edge caching: Pay per request, worth it for expensive origin calls

If your origin API costs $0.01/request and edge caching achieves 90% hit rate, you save $0.009/request—easily covering edge caching costs.

Making the Decision

Choose CDN if:

• Primarily serving static assets
• Simple caching rules suffice
• Budget is the primary concern
• No personalization needed

Choose Edge Caching if:

• Caching API responses
• Need custom cache logic
• Serving personalized content
• Require ML-powered optimization
• Global sub-50ms latency is critical

Conclusion

The choice between CDN and edge caching depends on your content type. Static sites thrive on traditional CDNs. Dynamic applications with APIs benefit from intelligent edge caching. Most production systems use both layers together for optimal performance.