Debugging (3)

Last updated Apr 23, 2026 The Cloudflare Vite plugin has debugging enabled by default and listens on port 9229. You may choose a custom port or disable debugging by setting the inspectorPort option in the plugin config. There are two recommended methods for debugging your Workers during local development:

DevTools

When running vite dev or vite preview, a /__debug route is added that provides access to Cloudflare's implementation ↗︎ of Chrome's DevTools ↗︎. Navigating to this route will open a DevTools tab for each of the Workers in your application.

Once the tab(s) are open, you can make a request to your application and start debugging your Worker code.

Note

When debugging multiple Workers, you may need to allow your browser to open pop-ups.

VS Code

To set up VS Code ↗︎ to support breakpoint debugging in your application, you should create a .vscode/launch.json file that contains the following configuration:

.vscode/launch.jsonjson

{
    "configurations": [
        {
            "name": "<NAME_OF_WORKER>",
            "type": "node",
            "request": "attach",
            "websocketAddress": "ws://localhost:9229/<NAME_OF_WORKER>",
            "resolveSourceMapLocations": null,
            "attachExistingChildren": false,
            "autoAttachChildProcesses": false,
            "sourceMaps": true
        }
    ],
    "compounds": [
        {
            "name": "Debug Workers",
            "configurations": ["<NAME_OF_WORKER>"],
            "stopAll": true
        }
    ]
}

Here, <NAME_OF_WORKER> indicates the name of the Worker as specified in your Worker config file. If you have used the inspectorPort option to set a custom port then this should be the value provided in the websocketaddress field.

Note

If you have more than one Worker in your application, you should add a configuration in the configurations field for each and include the configuration name in the compounds configurations array.

With this set up, you can run vite dev or vite preview and then select Debug Workers at the top of the Run & Debug panel to start debugging.

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description: Migrating from wrangler dev to the Vite plugin title: Migrating from wrangler dev image: https://developers.cloudflare.com/workers/vite-plugin/reference/migrating-from-wrangler-dev/og.png?v=d2679690dae58e73

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