Fetch Handler

Background

Incoming HTTP requests to a Worker are passed to the fetch() handler as a Request object. To respond to the request with a response, return a Response object:

JavaScript

export default {
  async fetch(request, env, ctx) {
    return new Response('Hello World!');
  },
};

Note

The Workers runtime does not support XMLHttpRequest (XHR). Learn the difference between XMLHttpRequest and fetch() in the MDN ↗ documentation.

Parameters

• request Request

  • The incoming HTTP request.

• env object

  • The bindings available to the Worker. As long as the environment has not changed, the same object (equal by identity) may be passed to multiple requests.

• ctx.waitUntil(promisePromise) : void

  • Refer to waitUntil.

• ctx.passThroughOnException() : void

  • Refer to passThroughOnException.