next.js/docs/01-app/03-api-reference/05-config/03-eslint.mdx

---
title: ESLint Plugin
nav_title: ESLint
description: Learn how to use and configure the ESLint plugin to catch common issues and problems in a Next.js application.
---

{/* The content of this doc is shared between the app and pages router. You can use the `<PagesOnly>Content</PagesOnly>` component to add content that is specific to the Pages Router. Any shared content should not be wrapped in a component. */}

Next.js provides an ESLint plugin, [`eslint-plugin-next`](https://www.npmjs.com/package/@next/eslint-plugin-next), already bundled within the base configuration that makes it possible to catch common issues and problems in a Next.js application.

## Reference

Recommended rule-sets from the following ESLint plugins are all used within `eslint-config-next`:

- [`eslint-plugin-react`](https://www.npmjs.com/package/eslint-plugin-react)
- [`eslint-plugin-react-hooks`](https://www.npmjs.com/package/eslint-plugin-react-hooks)
- [`eslint-plugin-next`](https://www.npmjs.com/package/@next/eslint-plugin-next)

This will take precedence over the configuration from `next.config.js`.

### Rules

The full set of rules is as follows:

| Enabled in recommended config | Rule                                                                                                                     | Description                                                                                                      |
| :---------------------------: | ------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------- |
|      <Check size={18} />      | [@next/next/google-font-display](/docs/messages/google-font-display)                                                     | Enforce font-display behavior with Google Fonts.                                                                 |
|      <Check size={18} />      | [@next/next/google-font-preconnect](/docs/messages/google-font-preconnect)                                               | Ensure `preconnect` is used with Google Fonts.                                                                   |
|      <Check size={18} />      | [@next/next/inline-script-id](/docs/messages/inline-script-id)                                                           | Enforce `id` attribute on `next/script` components with inline content.                                          |
|      <Check size={18} />      | [@next/next/next-script-for-ga](/docs/messages/next-script-for-ga)                                                       | Prefer `next/script` component when using the inline script for Google Analytics.                                |
|      <Check size={18} />      | [@next/next/no-assign-module-variable](/docs/messages/no-assign-module-variable)                                         | Prevent assignment to the `module` variable.                                                                     |
|      <Check size={18} />      | [@next/next/no-async-client-component](/docs/messages/no-async-client-component)                                         | Prevent Client Components from being async functions.                                                            |
|      <Check size={18} />      | [@next/next/no-before-interactive-script-outside-document](/docs/messages/no-before-interactive-script-outside-document) | Prevent usage of `next/script`'s `beforeInteractive` strategy outside of `pages/_document.js`.                   |
|      <Check size={18} />      | [@next/next/no-css-tags](/docs/messages/no-css-tags)                                                                     | Prevent manual stylesheet tags.                                                                                  |
|      <Check size={18} />      | [@next/next/no-document-import-in-page](/docs/messages/no-document-import-in-page)                                       | Prevent importing `next/document` outside of `pages/_document.js`.                                               |
|      <Check size={18} />      | [@next/next/no-duplicate-head](/docs/messages/no-duplicate-head)                                                         | Prevent duplicate usage of `<Head>` in `pages/_document.js`.                                                     |
|      <Check size={18} />      | [@next/next/no-head-element](/docs/messages/no-head-element)                                                             | Prevent usage of `<head>` element.                                                                               |
|      <Check size={18} />      | [@next/next/no-head-import-in-document](/docs/messages/no-head-import-in-document)                                       | Prevent usage of `next/head` in `pages/_document.js`.                                                            |
|      <Check size={18} />      | [@next/next/no-html-link-for-pages](/docs/messages/no-html-link-for-pages)                                               | Prevent usage of `<a>` elements to navigate to internal Next.js pages.                                           |
|      <Check size={18} />      | [@next/next/no-img-element](/docs/messages/no-img-element)                                                               | Prevent usage of `<img>` element due to slower LCP and higher bandwidth.                                         |
|      <Check size={18} />      | [@next/next/no-page-custom-font](/docs/messages/no-page-custom-font)                                                     | Prevent page-only custom fonts.                                                                                  |
|      <Check size={18} />      | [@next/next/no-script-component-in-head](/docs/messages/no-script-component-in-head)                                     | Prevent usage of `next/script` in `next/head` component.                                                         |
|      <Check size={18} />      | [@next/next/no-styled-jsx-in-document](/docs/messages/no-styled-jsx-in-document)                                         | Prevent usage of `styled-jsx` in `pages/_document.js`.                                                           |
|      <Check size={18} />      | [@next/next/no-sync-scripts](/docs/messages/no-sync-scripts)                                                             | Prevent synchronous scripts.                                                                                     |
|      <Check size={18} />      | [@next/next/no-title-in-document-head](/docs/messages/no-title-in-document-head)                                         | Prevent usage of `<title>` with `Head` component from `next/document`.                                           |
|      <Check size={18} />      | @next/next/no-typos                                                                                                      | Prevent common typos in [Next.js's data fetching functions](/docs/pages/building-your-application/data-fetching) |
|      <Check size={18} />      | [@next/next/no-unwanted-polyfillio](/docs/messages/no-unwanted-polyfillio)                                               | Prevent duplicate polyfills from Polyfill.io.                                                                    |

We recommend using an appropriate [integration](https://eslint.org/docs/user-guide/integrations#editors) to view warnings and errors directly in your code editor during development.

## Examples

### Linting custom directories and files

By default, Next.js will run ESLint for all files in the `pages/`, `app/`, `components/`, `lib/`, and `src/` directories. However, you can specify which directories using the `dirs` option in the `eslint` config in `next.config.js` for production builds:

```js filename="next.config.js"
module.exports = {
  eslint: {
    dirs: ['pages', 'utils'], // Only run ESLint on the 'pages' and 'utils' directories during production builds (next build)
  },
}
```

Similarly, the `--dir` and `--file` flags can be used for `next lint` to lint specific directories and files:

```bash filename="Terminal"
next lint --dir pages --dir utils --file bar.js
```

### Specifying a root directory within a monorepo

If you're using `eslint-plugin-next` in a project where Next.js isn't installed in your root directory (such as a monorepo), you can tell `eslint-plugin-next` where to find your Next.js application using the `settings` property in your `.eslintrc`:

```js filename="eslint.config.mjs"
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat({
  // import.meta.dirname is available after Node.js v20.11.0
  baseDirectory: import.meta.dirname,
})

const eslintConfig = [
  ...compat.config({
    extends: ['next'],
    settings: {
      next: {
        rootDir: 'packages/my-app/',
      },
    },
  }),
]

export default eslintConfig
```

`rootDir` can be a path (relative or absolute), a glob (i.e. `"packages/*/"`), or an array of paths and/or globs.

### Disabling the cache

To improve performance, information of files processed by ESLint are cached by default. This is stored in `.next/cache` or in your defined [build directory](/docs/app/api-reference/config/next-config-js/distDir). If you include any ESLint rules that depend on more than the contents of a single source file and need to disable the cache, use the `--no-cache` flag with `next lint`.

```bash filename="Terminal"
next lint --no-cache
```

### Disabling rules

If you would like to modify or disable any rules provided by the supported plugins (`react`, `react-hooks`, `next`), you can directly change them using the `rules` property in your `.eslintrc`:

```js filename="eslint.config.mjs"
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat({
  // import.meta.dirname is available after Node.js v20.11.0
  baseDirectory: import.meta.dirname,
})

const eslintConfig = [
  ...compat.config({
    extends: ['next'],
    rules: {
      'react/no-unescaped-entities': 'off',
      '@next/next/no-page-custom-font': 'off',
    },
  }),
]

export default eslintConfig
```

### With Core Web Vitals

The `next/core-web-vitals` rule set is enabled when `next lint` is run for the first time and the **strict** option is selected.

```js filename="eslint.config.mjs"
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat({
  // import.meta.dirname is available after Node.js v20.11.0
  baseDirectory: import.meta.dirname,
})

const eslintConfig = [
  ...compat.config({
    extends: ['next/core-web-vitals'],
  }),
]

export default eslintConfig
```

`next/core-web-vitals` updates `eslint-plugin-next` to error on a number of rules that are warnings by default if they affect [Core Web Vitals](https://web.dev/vitals/).

> The `next/core-web-vitals` entry point is automatically included for new applications built with [Create Next App](/docs/app/api-reference/cli/create-next-app).

### With TypeScript

In addition to the Next.js ESLint rules, `create-next-app --typescript` will also add TypeScript-specific lint rules with `next/typescript` to your config:

```js filename="eslint.config.mjs"
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat({
  // import.meta.dirname is available after Node.js v20.11.0
  baseDirectory: import.meta.dirname,
})

const eslintConfig = [
  ...compat.config({
    extends: ['next/core-web-vitals', 'next/typescript'],
  }),
]

export default eslintConfig
```

Those rules are based on [`plugin:@typescript-eslint/recommended`](https://typescript-eslint.io/linting/configs#recommended).
See [typescript-eslint > Configs](https://typescript-eslint.io/linting/configs) for more details.

### With Prettier

ESLint also contains code formatting rules, which can conflict with your existing [Prettier](https://prettier.io/) setup. We recommend including [eslint-config-prettier](https://github.com/prettier/eslint-config-prettier) in your ESLint config to make ESLint and Prettier work together.

First, install the dependency:

```bash filename="Terminal"
npm install --save-dev eslint-config-prettier

yarn add --dev eslint-config-prettier

pnpm add --save-dev eslint-config-prettier

bun add --dev eslint-config-prettier
```

Then, add `prettier` to your existing ESLint config:

```js filename="eslint.config.mjs"
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat({
  // import.meta.dirname is available after Node.js v20.11.0
  baseDirectory: import.meta.dirname,
})

const eslintConfig = [
  ...compat.config({
    extends: ['next', 'prettier'],
  }),
]

export default eslintConfig
```

### Running lint on staged files

If you would like to use `next lint` with [lint-staged](https://github.com/okonet/lint-staged) to run the linter on staged git files, you'll have to add the following to the `.lintstagedrc.js` file in the root of your project in order to specify usage of the `--file` flag.

```js filename=".lintstagedrc.js"
const path = require('path')

const buildEslintCommand = (filenames) =>
  `next lint --fix --file ${filenames
    .map((f) => path.relative(process.cwd(), f))
    .join(' --file ')}`

module.exports = {
  '*.{js,jsx,ts,tsx}': [buildEslintCommand],
}
```

## Disabling linting during production builds

If you do not want ESLint to run during `next build`, you can set the `eslint.ignoreDuringBuilds` option in `next.config.js` to `true`:

```ts filename="next.config.ts" switcher
import type { NextConfig } from 'next'

const nextConfig: NextConfig = {
  eslint: {
    // Warning: This allows production builds to successfully complete even if
    // your project has ESLint errors.
    ignoreDuringBuilds: true,
  },
}

export default nextConfig
```

```js filename="next.config.js" switcher
const nextConfig = {
  eslint: {
    // Warning: This allows production builds to successfully complete even if
    // your project has ESLint errors.
    ignoreDuringBuilds: true,
  },
}

export default nextConfig
```

### Migrating existing config

If you already have ESLint configured in your application, we recommend extending from this plugin directly instead of including `eslint-config-next` unless a few conditions are met.

#### Recommended plugin ruleset

If the following conditions are true:

- You have one or more of the following plugins already installed (either separately or through a different config such as `airbnb` or `react-app`):
  - `react`
  - `react-hooks`
  - `jsx-a11y`
  - `import`
- You've defined specific `parserOptions` that are different from how Babel is configured within Next.js (this is not recommended unless you have [customized your Babel configuration](/docs/pages/guides/babel))
- You have `eslint-plugin-import` installed with Node.js and/or TypeScript [resolvers](https://github.com/benmosher/eslint-plugin-import#resolvers) defined to handle imports

Then we recommend either removing these settings if you prefer how these properties have been configured within [`eslint-config-next`](https://github.com/vercel/next.js/blob/canary/packages/eslint-config-next/index.js) or extending directly from the Next.js ESLint plugin instead:

```js
module.exports = {
  extends: [
    //...
    'plugin:@next/next/recommended',
  ],
}
```

The plugin can be installed normally in your project without needing to run `next lint`:

```bash filename="Terminal"
npm install --save-dev @next/eslint-plugin-next

yarn add --dev @next/eslint-plugin-next

pnpm add --save-dev @next/eslint-plugin-next

bun add --dev @next/eslint-plugin-next
```

This eliminates the risk of collisions or errors that can occur due to importing the same plugin or parser across multiple configurations.

#### Additional configurations

If you already use a separate ESLint configuration and want to include `eslint-config-next`, ensure that it is extended last after other configurations. For example:

```js filename="eslint.config.mjs"
import js from '@eslint/js'
import { FlatCompat } from '@eslint/eslintrc'

const compat = new FlatCompat({
  // import.meta.dirname is available after Node.js v20.11.0
  baseDirectory: import.meta.dirname,
  recommendedConfig: js.configs.recommended,
})

const eslintConfig = [
  ...compat.config({
    extends: ['eslint:recommended', 'next'],
  }),
]

export default eslintConfig
```

The `next` configuration already handles setting default values for the `parser`, `plugins` and `settings` properties. There is no need to manually re-declare any of these properties unless you need a different configuration for your use case.

If you include any other shareable configurations, **you will need to make sure that these properties are not overwritten or modified**. Otherwise, we recommend removing any configurations that share behavior with the `next` configuration or extending directly from the Next.js ESLint plugin as mentioned above.