🐛 Attaching a Debugger

You can use regular Node.js tools to debug your workers. Setting breakpoints, watching values and inspecting the call stack are all examples of things you can do with a debugger.

If you're building your worker beforehand (e.g. with esbuild, Webpack, Rollup), make sure you're outputting 🗺 Source Maps before proceeding.

​Visual Studio Code

​Create configuration

The easiest way to debug a Worker in VSCode is to create a new configuration.

Open the Run and Debug menu in the VSCode activity bar and create a .vscode/launch.json file that contains the following:

.vscode/launch.json
{
  "configurations": [
    {
      "name": "Miniflare",
      "type": "node",
      "request": "attach",
      "port": 9229,
      "cwd": "/",
      "resolveSourceMapLocations": null,
      "attachExistingChildren": false,
      "autoAttachChildProcesses": false,
    }
  ]
}

From the Run and Debug menu in the activity bar, select the Miniflare configuration, and click the green play button to start debugging.

​WebStorm

Create a new configuration, by clicking Add Configuration in the top right.

Click the plus button in the top left of the popup and create a new Node.js/Chrome configuration. Set the Host field to localhost and the Port field to 9229. Then click OK.

With the new configuration selected, click the green debug button to start debugging.

​DevTools

Breakpoints can also be added via the Workers DevTools. For more information, read the guideOpen external link in the Cloudflare Workers docs.