netlify-edge-functions

Netlify Edge Functions

Reach for this (modern): default-export handler + inline config export with a narrowly-scoped path. Import types from @netlify/edge-functions.

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

export default async (request: Request, context: Context) => {
  // return Response | URL (rewrite) | undefined (continue chain)
};

export const config: Config = { path: "/products/*" };

Avoid: import maps in deno.json (unsupported — use a separate file via deno_import_map). Do not hand-write a function your framework's adapter already generates (Next.js, Astro, Remix, SvelteKit, Nuxt, etc.) — check the framework adapter/reference first; duplicating adapter middleware causes conflicts.

File location

• Default directory: YOUR_BASE_DIRECTORY/netlify/edge-functions.
• Custom directory: edge_functions key under [build] in netlify.toml. Keep it outside the publish directory so source files aren't deployed.
• .js/.ts/.jsx/.tsx all supported. If a .ts and .js file share a name, the .ts is ignored and the .js deploys.

⚠️ A function without a route silently never runs

Edge functions are not auto-assigned a URL. No config export and no netlify.toml declaration = deploys clean, no build error, no warning, never executes. If "my edge function does nothing," check the route first.

Request handling patterns

Handler receives (request: Request, context: Context). Return one of:

• Response — respond directly (ends the chain; declared redirects for the path do not run)
• URL — rewrite to a same-site URL with 200 status (address bar unchanged)
• undefined / empty return; — bypass this function, continue the chain

Netlify adds no headers to edge requests — use context for client info.

Redirect

export default async (req: Request, { cookies, geo }: Context) => {
  if (geo.city === "Paris" && cookies.get("promo-code") === "15-for-followers") {
    return Response.redirect(new URL("/subscriber-sale", req.url));
  }
};