Skip to content
Visit Miniflare on GitHub
Set theme to dark (โ‡ง+D)

๐Ÿ“š Modules

Enabling Modules

Miniflare supports both the traditional service-worker and newer modules formats for writing workers. To use the modules format, enable it with:

$ miniflare --modules # or -m
format = "modules"
const mf = new Miniflare({
modules: true,

When using the API you must also pass the --experimental-vm-modules flag to Node.js. This is added automatically when using the CLI.

You can now use modules worker scripts like the following:

export default {
async fetch(request, env, ctx) {
// - `request` is the incoming `Request` instance
// - `env` contains bindings, KV namespaces, Durable Objects, etc
// - `ctx` contains `waitUntil` and `passThroughOnException` methods
return new Response("Hello Miniflare!");
async scheduled(controller, env, ctx) {
// - `controller` contains `scheduledTime` and `cron` properties
// - `env` contains bindings, KV namespaces, Durable Objects, etc
// - `ctx` contains the `waitUntil` method
console.log("Doing something scheduled...");

Module Rules

Miniflare supports all module types: ESModule, CommonJS, Text, Data and CompiledWasm. You can specify additional module resolution rules as follows:

# Note all rules implicitly have the `fallthrough` option set to true
$ miniflare --modules-rule "ESModule=**/*.js" --modules-rule "Text=**/*.txt"
type = "ESModule"
globs = ["**/*.js"]
type = "Text"
globs = ["**/*.txt"]
const mf = new Miniflare({
modulesRules: [
{ type: "ESModule", include: ["**/*.js"], fallthrough: true },
{ type: "Text", include: ["**/*.txt"] },

Default Rules

The following rules are automatically added to the end of your modules rules list. You can override them by specifying rules matching the same globs:

type = "ESModule"
globs = ["**/*.mjs"]
type = "CommonJS"
globs = ["**/*.js", "**/*.cjs"]