netlify-edge-functions

Netlify Edge Functions

Modern syntax (reach for this)

Export a default handler plus a config object. Import Config/Context types from @netlify/edge-functions; Request/Response/URL are global.

import type { Config, Context } from "@netlify/edge-functions";

export default async (request: Request, context: Context) => {
  return new Response("Hello world");
};

export const config: Config = {
  path: "/test",
};

Do not hand-write an edge function when your framework's adapter already generates middleware for the job — duplicating it causes conflicts. Check the framework adapter/reference first.

Edge vs serverless: use edge functions for low-latency request/response manipulation, geolocation logic, auth checks/redirects, and A/B personalization. Use serverless functions for long-running work (up to 15 min), heavy Node.js dependencies, database-heavy operations, background/scheduled tasks, or memory above 512 MB.

File location

• Default directory: YOUR_BASE_DIRECTORY/netlify/edge-functions. Custom: edge_functions under [build] in netlify.toml (path relative to base directory).
• Keep the directory outside your publish directory so source files aren't deployed.
• Extensions: .js, .ts, .jsx, .tsx (.jsx/.tsx useful for SSR).
• Same-name conflict: if my-function.ts and my-function.js both exist, the TypeScript file is ignored and the JavaScript one is deployed.

Routing — required, or the function silently never runs

⚠️ An edge function without a route (no config export and no netlify.toml declaration) still deploys but never runs — no build error, no warning. When "my edge function does nothing", check the route first.

⚠️ Scope path narrowly. path: "/*" intercepts every request including static assets, adding latency and billing an edge invocation for each one.

Edge functions are not auto-assigned a URL route. Configure via inline config or netlify.toml.

path is a URLPattern expression, must start with /, single string or array: