Run multiple Cloudflare workers locally

When you’re testing an application locally, you ideally want an environment that mimics production as much as possible. Especially when you’re using multiple Cloudflare workers, you’ll want to make sure you can run them together for end-to-end testing during development. Without this ability, you either need to run everything in the cloud (problematic when your internet connection is down or slow) and test each worker individually.

Wrangler is capable of running multiple workers at the same time, like this:

npx wrangler dev -c worker1/wrangler.jsonc -c worker2/wrangler.jsonc

This is important because workers run together in one dev session share resources, including queues, and can communicate with one another. That’s key for creating a production-like environment locally.

However, Wrangler only starts one server for all workers and there’s no way to route between them. After some digging, I found this note in the docs:

You can provide multiple configuration files to run multiple Workers in one dev session like this: wrangler dev -c ./wrangler.toml -c ../other-worker/wrangler.toml. The first config will be treated as the primary Worker, which will be exposed over HTTP. The remaining config files will only be accessible via a service binding from the primary Worker.

That means we need the first worker listed to both list other workers as service bindings and route requests to the correct worker.

The `http` worker

You can create a simple worker, that I name http, to handle this for you. The first step is to list your other services in the wrangler.jsonc file:

{
    "$schema": "node_modules/wrangler/config-schema.json",
    "name": "http",
    "main": "src/index.ts",
    "compatibility_date": "2025-08-22",
    "services": [
        {
            "binding": "worker1",
            "service": "worker1"
        },
        {
            "binding": "worker2",
            "service": "worker2"
        }
    ]
}

Next, you’ll use Hono to route requests based on the request path. To make things easy, the path will be the worker binding name, which means you’ll only need to update the wrangler.jsonc file when you want to add or remove workers. Here’s the code:

import { Hono } from "hono";

interface Bindings {
    [binding: string]: Fetcher;
}

const app = new Hono<{ Bindings: Bindings }>();

app.all("/:worker/*", (c) => {
    const worker = c.req.param("worker");
    const binding = c.env[worker];

    if (!binding || typeof binding.fetch !== "function") {
        return c.text(`Worker binding '${worker}' not found`, 404);
    }

    // Rewrite the URL to remove the worker prefix
    const url = URL.parse(c.req.url) as URL;
    url.pathname = url.pathname.slice(`/${worker}`.length) || "/";

    // create a new request object to avoid issues with reused requests
    const request = new Request(url, c.req.raw.clone());

    return binding.fetch(request);
});

export default app;

Note that you need to pass c.req.raw to the worker rather than c.req, which is a Hono-specific object. In this way, all of the request information is passed directly to the worker. (You can, optionally, modify it as necessary.)

Now, make sure that the http worker is the first one passed to Wrangler:

npx wrangler dev -c http/wrangler.jsonc -c worker1/wrangler.jsonc -c worker2/wrangler.jsonc

Then you can test out your workers locally:

# call worker1
curl -i -X POST http://localhost:8787/worker1 \
    -H "Content-Type: application/json" \
    -d '{"message":"Hello worker1!"}'

# call worker2
curl -i -X POST http://localhost:8787/worker2 \
    -H "Content-Type: application/json" \
    -d '{"message":"Hello worker2!"}'