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---
title: Improved support for running multiple Workers with `wrangler dev`
description: Workers running with wrangler dev using multiple config files can now communicate with Workers running in separate dev commands.
products:
- workers
date: 2025-09-23
---

You can run multiple Workers in a single dev command by passing multiple config files to `wrangler dev`:

```sh
wrangler dev --config ./web/wrangler.jsonc --config ./api/wrangler.jsonc
```

Previously, if you ran the command above and then also ran wrangler dev for a different Worker, the Workers running in separate wrangler dev sessions could not communicate with each other. This prevented you from being able to use [Service Bindings](https://developers.cloudflare.com/workers/runtime-apis/bindings/service-bindings/) and [Tail Workers](https://developers.cloudflare.com/workers/observability/logs/tail-workers/) in local development, when running separate wrangler dev sessions.

Now, the following works as expected:

```sh
# Terminal 1: Run your application that includes both Web and API workers
wrangler dev --config ./web/wrangler.jsonc --config ./api/wrangler.jsonc

# Terminal 2: Run your auth worker separately
wrangler dev --config ./auth/wrangler.jsonc
```

These Workers can now communicate with each other across separate dev commands, regardless of your development setup.

```js title="./api/src/index.ts"
export default {
async fetch(request, env) {
// This service binding call now works across dev commands
const authorized = await env.AUTH.isAuthorized(request);

if (!authorized) {
return new Response('Unauthorized', { status: 401 });
}

return new Response('Hello from API Worker!', { status: 200 });
},
};
```

Check out the [Developing with multiple Workers](/workers/development-testing/multi-workers) guide to learn more about the different approaches and when to use each one.
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