Get Started

To deploy your first Function, you’ll need to create a /functions directory at the root of your project. Writing your Functions files in this directory will automatically generate a Worker with custom functionality at predesignated routes. For example, let’s take the Function:

helloworld.js
export function onRequest(context) {
  return new Response("Hello, world!")
}

The onRequest handler takes a “request context” object which we’ll cover in more detail below. The handler must return a Response or a Promise of a Response.

This function will run on the /helloworld route and returns “hello world!”. The reason this function is available on this route is because the file is named helloworld.js. Similarly, if this file was called howdyworld.js, this function would run on /howdyworld.

Let’s take a closer look at how this routing behavior works and how to further customize this.