Post-Cache Edge Functions

Post-cache edge functions run after the response is served from cache, allowing you to modify cached responses without invalidating the cache. This is useful for adding dynamic headers, analytics, or other post-processing to cached content.

To create a post-cache edge function, set cache = "manual" in the edge function configuration:

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

export default async (request: Request, context: Context) => {
  const url = new URL(request.url);

  // Get the response from the origin/cache
  const response = await context.next();

  // Modify the response
  const modifiedResponse = new Response(response.body, response);
  modifiedResponse.headers.set(
    "X-Post-Cache-Processed",
    new Date().toISOString()
  );

  return modifiedResponse;
};

export const config: Config = {
  path: "/*",
  cache: "manual",
};

Key Points

• Post-cache functions run after non-cached edge functions
• They can modify responses that have been served from cache
• The cache = "manual" setting enables this behavior
• Useful for adding analytics, dynamic headers, or response transformation

See this in action

Use the links below to see the post-cache edge function in action. Check the response headers in your browser's developer tools to see the X-Post-Cache-Processed header.

• View /hello without post-cache processing
• View /hello with post-cache edge function (check response headers)
• The Edge Function code: post-cache.ts