Edge computing brings computation closer to users—running code at CDN edge locations worldwide rather than centralized data centers. This fundamental shift enables new performance and personalization capabilities for web applications.
What Is Edge Computing?
Traditional Architecture
User (Tokyo) → CDN (static) → Origin Server (US-East) → Response
└── 200ms latency
Edge Architecture
User (Tokyo) → Edge Function (Tokyo) → Response
└── 20ms latency
Edge functions run at hundreds of locations globally, processing requests milliseconds from users.
Edge Platforms
Major Providers
Cloudflare Workers
- V8 isolates
- 0ms cold start
- 200+ locations
Vercel Edge Functions
- Built on Cloudflare
- Next.js integration
- Edge middleware
AWS Lambda@Edge / CloudFront Functions
- CloudFront integration
- Regional edge caches
- Origin request/response
Deno Deploy
- Deno runtime
- TypeScript native
- Global deployment
Edge Function Basics
Cloudflare Workers
Vercel Edge Functions
Common Use Cases
Geolocation and Personalization
A/B Testing
Authentication at the Edge
Rate Limiting
Edge Middleware
Next.js Middleware
Data at the Edge
Key-Value Storage
Durable Objects (Stateful Edge)
Limitations and Trade-offs
Edge Constraints
Limited capabilities:
- No filesystem access
- Limited CPU time (50ms - 30s depending on plan)
- Memory limits (128MB - 512MB)
- No persistent connections to databases
- Limited Node.js API compatibility
Solutions:
- Use edge-compatible libraries
- Cache database results in KV
- Use edge-native databases (PlanetScale, Turso)
- Fallback to regional functions for complex operations
When NOT to Use Edge
Keep at origin:
- Complex database queries
- Long-running operations
- Heavy computation
- Large file processing
- Operations requiring full Node.js API
Use edge for:
- Routing and redirects
- Authentication checks
- Personalization
- A/B testing
- Static asset optimization
- Simple API responses
Hybrid Architecture
┌─────────────────────────────────────────────┐
│ User │
└─────────────────────┬───────────────────────┘
│
┌─────────────────────▼───────────────────────┐
│ Edge Function │
│ - Auth check │
│ - Geo-personalization │
│ - Route decision │
└─────────────┬───────────────┬───────────────┘
│ │
┌─────────▼─────────┐ ┌───▼────────────────┐
│ Static Assets │ │ Origin Server │
│ (CDN Cache) │ │ (Complex Logic) │
└──────────────────┘ └────────────────────┘
Deployment
Cloudflare Workers
Vercel Edge
Conclusion
Edge computing fundamentally changes web architecture—moving computation from centralized origins to distributed edge locations milliseconds from users. This enables personalization, security, and performance improvements impossible with traditional architectures.
Start with simple use cases: authentication, redirects, or personalization. As you gain experience, expand to more complex edge logic. The future of web development is increasingly at the edge.