Edge Functions
Server code that runs in data centers closest to your user — making your app respond in milliseconds instead of seconds.
💡 In plain English: Instead of your app's brain being in one city, edge puts copies everywhere — so users in Tokyo get the same speed as users in New York.
Quick answer
Edge functions are server-side code that runs on a globally distributed network of servers, executing in the data center closest to each user. Unlike traditional servers in one location, edge functions run in 300+ locations worldwide with no cold starts.
What is Edge Functions?
Traditional servers run in one location — say, US East. A user in Tokyo waits 200ms just for the network round trip, before your code even runs. Edge functions solve this by running your code in 300+ data centers worldwide.
Edge functions use V8 isolates (the JavaScript engine from Chrome) instead of full virtual machines. They start in under 1ms with no cold starts, compared to 500ms-3s for traditional serverless functions.
Use edge for: auth middleware, redirects, A/B testing, API rate limiting. Don't use edge for: long-running tasks, heavy database queries, file processing.
In Vibe Coding
Cloudflare Workers is the most common edge runtime for vibe coders — gptsters.com runs on it. Vercel Edge Functions and Supabase Edge Functions are also popular. In Next.js, add 'export const runtime = "edge"' to any route to run it on the edge.
Example
For example: Your authentication middleware checks every request. Instead of running on one server in the US, it runs at the nearest edge location — so a user in London gets their request authenticated in 10ms instead of 200ms.
Simple edge function (Cloudflare Worker)
export default {
async fetch(request: Request): Promise<Response> {
const url = new URL(request.url)
if (url.pathname === '/api/hello') {
return Response.json({
message: 'Hello from the edge!',
location: request.cf?.country
})
}
return new Response('Not found', { status: 404 })
}
}Related Terms
Related Guides
Frequently Asked Questions
Edge runs in V8 isolates (fast, limited APIs). Serverless runs in full Node.js (slower startup, full features).
Yes — Cloudflare D1, Supabase, and PlanetScale all work from edge functions.