Backend

Edge Function

Server-side code that runs at the CDN edge, close to your users, for ultra-low latency responses.

The Full Picture

Edge functions run on the CDN edge (Vercel Edge, Cloudflare Workers, Deno Deploy) instead of a central server. They start in milliseconds and execute geographically close to the user. Great for: authentication checks, redirects, A/B testing, and lightweight API logic.

Limitations: no Node.js APIs (no fs, limited npm packages), short execution time limits, and restricted memory. AI tools sometimes generate Node.js code for edge functions that won't actually run there.

Related Terms

Serverless

Cloud functions that run your code on demand — no servers to manage, you only pay when they execute.

API Route

A server-side endpoint defined right in your Next.js project — no separate backend needed.

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