Edge computing moves computation closer to users. Instead of running all code in a central data center, edge functions execute at CDN nodes distributed around the world. The result is dramatically lower latency and a better user experience for global audiences.
This guide explains what edge computing is, how edge functions work, and when to use them.
What is edge computing?
Traditional cloud computing runs code in a few large data centers. A user in Tokyo might wait 200ms for a round trip to a server in Virginia. Edge computing runs code in dozens or hundreds of locations worldwide — the same CDN infrastructure that serves static assets now executes dynamic logic.
Key platforms:
- Cloudflare Workers: runs on Cloudflare's global network (330+ cities)
- Vercel Edge Functions: runs on Vercel's Edge Network
- Netlify Edge Functions: runs on Netlify's global edge network
- AWS Lambda@Edge: runs on CloudFront edge locations
What edge functions can do
Edge functions are serverless functions that run at edge locations. They share most serverless characteristics — no server management, pay-per-execution — but with geographic distribution built in.
Common use cases:
- Geolocation-based content: serve different content, prices, or languages based on the user's location without a round trip to the origin server
- A/B testing: route users to different experiment variants at the edge, avoiding client-side flicker
- Authentication checks: validate tokens at the edge before requests reach your origin server
- API response transformation: modify API responses (add headers, rewrite URLs, filter fields) before they reach the client
- Personalization: inject personalized content (recommendations, user-specific data) into cached pages
- Rate limiting and security: block malicious requests at the edge before they hit your infrastructure
Edge vs serverless: key differences
| Aspect | Serverless Functions | Edge Functions | |--------|---------------------|----------------| | Runtime | Node.js, Python, Go | V8 isolates (JavaScript, Wasm) | | Cold start | 100-500ms | near-zero (~5ms) | | Duration limit | up to 15 minutes | 10-50 seconds | | Location | single region | global (many locations) | | Memory | up to 10GB | up to 128MB |
Edge functions trade runtime flexibility for speed and global distribution. They cannot run long processes or use large amounts of memory, but they execute lightning-fast near users.
Building with edge functions
Edge functions follow a request-response pattern. A simple geolocation-based redirect in Cloudflare Workers:
export default {
async fetch(request, env, ctx) {
const country = request.cf?.country;
if (country === "GB") {
return Response.redirect("https://uk.example.com");
}
return fetch(request);
},
};
Edge functions integrate with your existing framework. Next.js supports export const runtime = "edge" at the route level, allowing individual pages or API routes to run at the edge.
When not to use edge functions
Edge functions aren't suitable for everything. Avoid them for database-heavy operations (no direct database connection from the edge), CPU-intensive computations, and long-running tasks. Use edge functions for the "first mile" of request handling — then pass complex work to origin servers.
Edge computing changes what's possible for web performance. Running code at the edge reduces latency, improves user experience, and enables architectures that were impractical a few years ago.
Building a global web application? At Vynta leverage edge functions to deliver fast, personalized experiences to users wherever they are.