Edge Computing for Web Applications

Edge Computing: Running Code Where Your Users Are

Edge computing is about running code as close to your users as possible. Instead of having a single data center in one location, you run your code on servers distributed around the world — at the edge of the network. This dramatically reduces latency because data doesn't have to travel long distances.

How Edge Computing Works

Traditional cloud computing runs your code in a few large data centers. If your server is in Virginia and a user is in Tokyo, every request travels across the Pacific Ocean and back, adding hundreds of milliseconds of delay. Edge computing distributes your code across hundreds or thousands of locations, so a user in Tokyo gets served by a server in Tokyo.

Edge computing platforms like Cloudflare Workers, Vercel Edge Functions, and Deno Deploy run your code on their CDN infrastructure. They use a different architecture than traditional servers — instead of running a full operating system for each request, they use lightweight isolates that start in microseconds. This means no cold starts, even at global scale.

What to Run at the Edge

Edge computing is ideal for tasks that need to be fast and personalized. Authentication checks can happen at the edge, verifying tokens and redirecting unauthenticated users without hitting your origin server. URL rewriting and redirects can be handled at the edge. A/B testing can assign users to variants before their request reaches your application.

Geolocation-based content is another natural fit. If you know where the user is, you can serve different content, language, or pricing at the edge. Personalization — like showing different content based on the user's device or browsing history — can be done without adding latency.

Limitations and Trade-offs

Edge computing isn't suitable for everything. Edge functions typically have limits on execution time (milliseconds, not seconds), memory (tens of megabytes, not gigabytes), and available APIs (no file system, limited database access). They're not designed for long-running processes or CPU-intensive computations.

The edge is also a different programming model. You can't assume that state is shared — each request might be handled by a different edge location. Databases need to be globally distributed or accessed through a connection pool. This adds complexity that you don't have with a traditional centralized server.

The Future

Edge computing is still evolving rapidly. As edge platforms add more capabilities and developers build more sophisticated applications, the line between edge and cloud will blur. The most likely future is a hybrid model where some logic runs at the edge for speed, and more complex processing runs in centralized servers. The goal is to give each user the fastest possible experience, regardless of where they are in the world.