netlify-edge-functions

Create a TypeScript or JavaScript file in netlify/edge-functions that default-exports an async handler receiving (request, context), and export a config object with a path. Import the Config and Context types from @netlify/edge-functions.

Edge functions are not auto-assigned a URL, so a missing config export or netlify.toml declaration means the function deploys but never executes. Check that a path route is declared first, since no build error or warning appears.

Use edge functions for low-latency request manipulation, geolocation, auth redirects, and personalization. Use serverless functions for long-running work up to 15 minutes, heavy Node dependencies, database operations, or memory needs above 512 MB.

Set cache: "manual" in the function config and return a Response with Cache-Control headers such as public, s-maxage=3600. Both parts are required; headers alone or config alone cache nothing.

Yes, npm package support is in beta: install packages and import them by name. Packages needing native binaries or runtime dynamic imports may fail, so prefer node: built-ins or Deno URL imports like esm.sh.

Limits include 20 MB compressed code size, 512 MB memory, and 50 ms CPU per request. Edge functions do not run with Split Testing enabled, custom headers do not apply, and prerendering is skipped for edge-served paths.