Support for Node.js DNS, Net, and Timer APIs in Workers

January 28, 2025

Support for Node.js DNS, Net, and Timer APIs in Workers

When using a Worker with the nodejs_compat compatibility flag enabled, you can now use the following Node.js APIs:

node:net

You can use node:net ↗ to create a direct connection to servers via a TCP sockets with net.Socket ↗.

index.jsjs

import net from "node:net";

const exampleIP = "127.0.0.1";

export default {
	async fetch(req) {
		const socket = new net.Socket();
		socket.connect(4000, exampleIP, function () {
			console.log("Connected");
		});

		socket.write("Hello, Server!");
		socket.end();

		return new Response("Wrote to server", { status: 200 });
	},
};

index.tsts

import net from "node:net";

const exampleIP = "127.0.0.1";

export default {
  async fetch(req): Promise<Response> {
    const socket = new net.Socket();
    socket.connect(4000, exampleIP, function () {
      console.log("Connected");
    });

    socket.write("Hello, Server!");
    socket.end();

    return new Response("Wrote to server", { status: 200 });
  },
} satisfies ExportedHandler;

Additionally, you can now use other APIs including net.BlockList ↗ and net.SocketAddress ↗.

Note that net.Server ↗ is not supported.

node:dns

You can use node:dns ↗ for name resolution via DNS over HTTPS using Cloudflare DNS ↗ at 1.1.1.1.

index.jsjs

import dns from "node:dns";

let response = await dns.promises.resolve4("cloudflare.com", "NS");

index.tsts

import dns from 'node:dns';

let response = await dns.promises.resolve4('cloudflare.com', 'NS');

All node:dns functions are available, except lookup, lookupService, and resolve which throw "Not implemented" errors when called.

node:timers

You can use node:timers ↗ to schedule functions to be called at some future period of time.

This includes setTimeout ↗ for calling a function after a delay, setInterval ↗ for calling a function repeatedly, and setImmediate ↗ for calling a function in the next iteration of the event loop.

index.jsjs

import timers from "node:timers";

console.log("first");
timers.setTimeout(() => {
	console.log("last");
}, 10);

timers.setTimeout(() => {
	console.log("next");
});

index.tsts

import timers from "node:timers";

console.log("first");
timers.setTimeout(() => {
  console.log("last");
}, 10);

timers.setTimeout(() => {
  console.log("next");
});