• Runtime APIs

The following APIs are the same as the Web APIS you already know. Additionally, we follow the WinterCG conventions.

Handler

The only required code to make your Function runnable is to export a handler function, that accepts a Request and returns a Response (or a promise returning a Response):

export function handler(request: Request): Response {
  return new Response('Hello World!');
}

Starting from this simple code, you can do whatever you whish, using the Web APIs you already know.

Global objects

console

Similar to the the standard console object on the browser and on Node.js, expect that it only supports the following methods:

• log
• info
• debug
• warn
• error

You can log multiple objects, and use string substitution. See the documentation on MDN.

process

The only usage of process is to get environment variables via process.env.

Example:

export function handler(request: Request): Response {
  return new Response(`My secret is: ${process.env.SECRET}`);
}

crypto

The standard crypto object.

crypto.randomUUID()

The standard randomUUID() method. See the documentation on MDN.

crypto.getRandomValues()

The standard getRandomValues() method. See the documentation on MDN.

crypto.subtle

The standard CryptoSubtle object. See the documentation on MDN.

TextEncoder

The standard TextEncoder object. See the documentation on MDN.

TextDecoder

The standard TextDecoder object. See the documentation on MDN.

AbortController

The standard AbortController object. See the documentation on MDN.

AbortSignal

The standard AbortSignal object. See the documentation on MDN.

Fetch

Request

The standard Request object. See the documentation on MDN.

Response

The standard Response object. See the documentation on MDN.

Streaming: You can pass a ReadableStream object as the body of a Response to stream the response as more data becomes available. Often, you won't need to implement the logic yourself as it is implemented by the frameworks and libraries you use.

URL

The standard URL object. See the documentation on MDN.

URLSearchParams

The standard URLSearchParams object. See the documentation on MDN.

Headers

The standard Headers object. See the documentation on MDN.

Streams

ReadableStream

The standard ReadableStream object. See the documentation on MDN.

ReadableStreamDefaultReader

The standard ReadableStreamDefaultReader object. See the documentation on MDN.

WritableStream

The standard WritableStream object. See the documentation on MDN.

WritableStreamDefaultWriter

The standard WritableStreamDefaultWriter object. See the documentation on MDN.

TransformStream

The standard TransformStream object. See the documentation on MDN.

Global methods

fetch()

The standard fetch method. See the documentation on MDN.

atob()

The standard atob method. See the documentation on MDN.

btoa()

The standard btoa method. See the documentation on MDN.