---
title: DevTools · Cloudflare Workers docs
description: When running your Worker locally using wrangler dev, you automatically have access to Cloudflare's implementation of Chrome's DevTools.
DevTools help you debug and optimize your Workers.
lastUpdated: 2025-02-05T10:06:53.000Z
source_url:
  html: https://kian-pcx-16407.preview.developers.cloudflare.com/workers/observability/dev-tools/index.md
  md: https://kian-pcx-16407.preview.developers.cloudflare.com/workers/observability/dev-tools/
---

## Using DevTools

When running your Worker locally using `wrangler dev`, you automatically have access to [Cloudflare's implementation](https://github.com/cloudflare/workers-sdk/tree/main/packages/chrome-devtools-patches) of [Chrome's DevTools](https://developer.chrome.com/docs/devtools/overview). DevTools help you debug and optimize your Workers.

Note

You may have experience using Chrome's DevTools for frontend development. Notably, Worker DevTools are used for backend code and *not* client-side JavaScript.

## Opening DevTools

To get started, run your Worker in development mode with `wrangler dev`, then open the DevTools in the browser by pressing the `D` key from your terminal. Now when you access this worker locally, it can be debugged and profiled with this DevTools instance.

Alternatively, both the [Cloudflare Dashboard](https://dash.cloudflare.com/) and the [Worker's Playground](https://workers.cloudflare.com/playground) include DevTools in their UI.

## DevTool use cases

DevTools can be used in a variety of situations. For more information, see the documentation:

* [Debugging code via breakpoints and logging](https://developers.cloudflare.com/workers/observability/dev-tools/breakpoints/)
* [Profiling CPU usage](https://developers.cloudflare.com/workers/observability/dev-tools/cpu-usage/)
* [Addressing out of memory (OOM) errors](https://developers.cloudflare.com/workers/observability/dev-tools/memory-usage/)

## Related resources

* [Local development](https://developers.cloudflare.com/workers/local-development/) - Develop your Workers and connected resources locally via Wrangler and workerd, for a fast, accurate feedback loop.
