---
description: Debug your Next.js app.
---
# Debugging
This documentation explains how you can debug your Next.js frontend and backend code with full source maps support using either the [VS Code debugger](https://code.visualstudio.com/docs/editor/debugging) or [Chrome DevTools](https://developers.google.com/web/tools/chrome-devtools).
Any debugger that can attach to Node.js can also be used to debug a Next.js application. You can find more details in the Node.js [Debugging Guide](https://nodejs.org/en/docs/guides/debugging-getting-started/).
## Debugging with VS Code
Create a file named `.vscode/launch.json` at the root of your project with the following content:
```json
{
"version": "0.2.0",
"configurations": [
{
"name": "Next.js: debug server-side",
"type": "node-terminal",
"request": "launch",
"command": "npm run dev"
},
{
"name": "Next.js: debug client-side",
"type": "pwa-chrome",
"request": "launch",
"url": "http://localhost:3000"
},
{
"name": "Next.js: debug full stack",
"type": "node-terminal",
"request": "launch",
"command": "npm run dev",
"console": "integratedTerminal",
"serverReadyAction": {
"pattern": "started server on .+, url: (https?://.+)",
"uriFormat": "%s",
"action": "debugWithChrome"
}
}
]
}
```
`npm run dev` can be replaced with `yarn dev` if you're using Yarn. If you're [changing the port number](/docs/api-reference/cli#development) your application starts on, replace the `3000` in `http://localhost:3000` with the port you're using instead.
Now go to the Debug panel (Ctrl+Shift+D on Windows/Linux, ⇧+⌘+D on macOS), select a launch configuration, then press F5 or select **Debug: Start Debugging** from the Command Palette to start your debugging session.
## Using the Debugger in Jetbrains WebStorm
Click the drop down menu listing the runtime configuration, and click `Edit Configurations...`. Create a `Javascript Debug` debug configuration with `http://localhost:3000` as the URL. Customize to your liking (e.g. Browser for debugging, store as project file), and click `OK`. Run this debug configuration, and the selected browser should automatically open. At this point, you should have 2 applications in debug mode: the NextJS node application, and the client/ browser application.
## Debugging with Chrome DevTools
### Client-side code
Start your development server as usual by running `next dev`, `npm run dev`, or `yarn dev`. Once the server starts, open `http://localhost:3000` (or your alternate URL) in Chrome. Next, open Chrome's Developer Tools (Ctrl+Shift+J on Windows/Linux, ⌥+⌘+I on macOS), then go to the **Sources** tab.
Now, any time your client-side code reaches a [`debugger`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/debugger) statement, code execution will pause and that file will appear in the debug area. You can also press Ctrl+P on Windows/Linux or ⌘+P on macOS to search for a file and set breakpoints manually. Note that when searching here, your source files will have paths starting with `webpack://_N_E/./`.
### Server-side code
To debug server-side Next.js code with Chrome DevTools, you need to pass the [`--inspect`](https://nodejs.org/api/cli.html#cli_inspect_host_port) flag to the underlying Node.js process:
```bash
NODE_OPTIONS='--inspect' next dev
```
If you're using `npm run dev` or `yarn dev` (see [Getting Started](/docs/getting-started)) then you should update the `dev` script on your `package.json`:
```json
"dev": "NODE_OPTIONS='--inspect' next dev"
```
Launching the Next.js dev server with the `--inspect` flag will look something like this:
```bash
Debugger listening on ws://127.0.0.1:9229/0cf90313-350d-4466-a748-cd60f4e47c95
For help, see: https://nodejs.org/en/docs/inspector
ready - started server on 0.0.0.0:3000, url: http://localhost:3000
```
> Be aware that running `NODE_OPTIONS='--inspect' npm run dev` or `NODE_OPTIONS='--inspect' yarn dev` won't work. This would try to start multiple debuggers on the same port: one for the npm/yarn process and one for Next.js. You would then get an error like `Starting inspector on 127.0.0.1:9229 failed: address already in use` in your console.
Once the server starts, open a new tab in Chrome and visit `chrome://inspect`, where you should see your Next.js application inside the **Remote Target** section. Click **inspect** under your application to open a separate DevTools window, then go to the **Sources** tab.
Debugging server-side code here works much like debugging client-side code with Chrome DevTools, except that when you search for files here with Ctrl+P or ⌘+P, your source files will have paths starting with `webpack://{application-name}/./` (where `{application-name}` will be replaced with the name of your application according to your `package.json` file).
### Debugging on Windows
Windows users may run into an issue when using `NODE_OPTIONS='--inspect'` as that syntax is not supported on Windows platforms. To get around this, install the [`cross-env`](https://www.npmjs.com/package/cross-env) package as a development dependency (`--dev` with NPM or `-D` for Yarn) and replace the `dev` script with the following.
```json
"dev": "cross-env NODE_OPTIONS='--inspect' next dev",
```
`cross-env` will set the `NODE_OPTIONS` environment variable regardless of which platform you are on (including Mac, Linux, and Windows) and allow you to debug consistently across devices and operating systems.
## More information
To learn more about how to use a JavaScript debugger, take a look at the following documentation:
- [Node.js debugging in VS Code: Breakpoints](https://code.visualstudio.com/docs/nodejs/nodejs-debugging#_breakpoints)
- [Chrome DevTools: Debug JavaScript](https://developers.google.com/web/tools/chrome-devtools/javascript)