ESLint

Next.js provides an ESLint configuration package, eslint-config-next, that makes it easy to catch common issues in your application. It includes the @next/eslint-plugin-next plugin along with recommended rule-sets from eslint-plugin-react and eslint-plugin-react-hooks.

The package provides two main configurations:

• eslint-config-next: Base configuration with Next.js, React, and React Hooks rules. Supports both JavaScript and TypeScript files.
• eslint-config-next/core-web-vitals: Includes everything from the base config, plus upgrades rules that impact Core Web Vitals from warnings to errors. Recommended for most projects.

Additionally, for TypeScript projects:

• eslint-config-next/typescript: Adds TypeScript-specific linting rules from typescript-eslint. Use this alongside the base or core-web-vitals config.

Setup ESLint

Get linting working quickly with the ESLint CLI (flat config):

1. Install ESLint and the Next.js config:

   pnpmnpmyarnbun

   Terminal

   pnpm add -D eslint eslint-config-next

2. Create eslint.config.mjs with the Next.js config:

   eslint.config.mjs

   import { defineConfig, globalIgnores } from 'eslint/config' import nextVitals from 'eslint-config-next/core-web-vitals'   const eslintConfig = defineConfig([  ...nextVitals,  // Override default ignores of eslint-config-next.  globalIgnores([  // Default ignores of eslint-config-next:  '.next/**',  'out/**',  'build/**',  'next-env.d.ts',  ]), ])   export default eslintConfig

3. Run ESLint:

   pnpmnpmyarnbun

   Terminal

   pnpm exec eslint .

Reference

The eslint-config-next package includes the recommended rule-sets from the following ESLint plugins:

• eslint-plugin-react
• eslint-plugin-react-hooks
• @next/eslint-plugin-next

Rules

The @next/eslint-plugin-next rules included are:

We recommend using an appropriate integration to view warnings and errors directly in your code editor during development.

Examples

Specifying a root directory within a monorepo

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

import { defineConfig } from 'eslint/config' import eslintNextPlugin from '@next/eslint-plugin-next'   const eslintConfig = defineConfig([  {  files: ['**/*.{js,jsx,ts,tsx}'],  plugins: {  next: eslintNextPlugin,  },  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 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 eslint.config.mjs:

import { defineConfig, globalIgnores } from 'eslint/config' import nextVitals from 'eslint-config-next/core-web-vitals'   const eslintConfig = defineConfig([  ...nextVitals,  {  rules: {  'react/no-unescaped-entities': 'off',  '@next/next/no-page-custom-font': 'off',  },  },  // Override default ignores of eslint-config-next.  globalIgnores([  // Default ignores of eslint-config-next:  '.next/**',  'out/**',  'build/**',  'next-env.d.ts',  ]), ])   export default eslintConfig

With Core Web Vitals

Enable the eslint-config-next/core-web-vitals configuration in your ESLint config.

import { defineConfig, globalIgnores } from 'eslint/config' import nextVitals from 'eslint-config-next/core-web-vitals'   const eslintConfig = defineConfig([  ...nextVitals,  // Override default ignores of eslint-config-next.  globalIgnores([  // Default ignores of eslint-config-next:  '.next/**',  'out/**',  'build/**',  'next-env.d.ts',  ]), ])   export default eslintConfig

eslint-config-next/core-web-vitals upgrades certain lint rules in @next/eslint-plugin-next from warnings to errors to help improve your Core Web Vitals metrics.

The eslint-config-next/core-web-vitals configuration is automatically included for new applications built with 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 eslint-config-next/typescript to your config:

import { defineConfig, globalIgnores } from 'eslint/config' import nextVitals from 'eslint-config-next/core-web-vitals' import nextTs from 'eslint-config-next/typescript'   const eslintConfig = defineConfig([  ...nextVitals,  ...nextTs,  // Override default ignores of eslint-config-next.  globalIgnores([  // Default ignores of eslint-config-next:  '.next/**',  'out/**',  'build/**',  'next-env.d.ts',  ]), ])   export default eslintConfig

Those rules are based on plugin:@typescript-eslint/recommended. See typescript-eslint > Configs for more details.

With Prettier

ESLint also contains code formatting rules, which can conflict with your existing Prettier setup. We recommend including eslint-config-prettier in your ESLint config to make ESLint and Prettier work together.

First, install the dependency:

pnpm add -D eslint-config-prettier

Then, add prettier to your existing ESLint config:

import { defineConfig, globalIgnores } from 'eslint/config' import nextVitals from 'eslint-config-next/core-web-vitals' import prettier from 'eslint-config-prettier/flat'   const eslintConfig = defineConfig([  ...nextVitals,  prettier,  // Override default ignores of eslint-config-next.  globalIgnores([  // Default ignores of eslint-config-next:  '.next/**',  'out/**',  'build/**',  'next-env.d.ts',  ]), ])   export default eslintConfig

Running lint on staged files

If you would like to use ESLint with lint-staged to run the linter on staged git files, add the following to the .lintstagedrc.js file in the root of your project:

const path = require('path')   const buildEslintCommand = (filenames) =>  `eslint --fix ${filenames  .map((f) => `"${path.relative(process.cwd(), f)}"`)  .join(' ')}`   module.exports = {  '*.{js,jsx,ts,tsx}': [buildEslintCommand], }

Migrating existing config

If you already have ESLint configured in your application, there are two approaches to integrate Next.js linting rules, depending on your setup.

Using the plugin directly

Use @next/eslint-plugin-next directly if you have any of the following already configured:

• Conflicting plugins installed separately or through another config (such as airbnb or react-app):
  • react
  • react-hooks
  • jsx-a11y
  • import
• Custom parserOptions different from Next.js defaults (only if you have customized your Babel configuration)
• eslint-plugin-import with custom Node.js and/or TypeScript resolvers

In these cases, use @next/eslint-plugin-next directly to avoid conflicts:

First, install the plugin:

pnpm add -D @next/eslint-plugin-next

Then add it to your ESLint config:

import { defineConfig } from 'eslint/config' import nextPlugin from '@next/eslint-plugin-next'   const eslintConfig = defineConfig([  // Your other configurations...  {  files: ['**/*.{js,jsx,ts,tsx}'],  plugins: {  '@next/next': nextPlugin,  },  rules: {  ...nextPlugin.configs.recommended.rules,  },  }, ])   export default eslintConfig

This approach eliminates the risk of collisions or errors that can occur when the same plugins or parsers are imported across multiple configurations.

Adding to existing config

If you're adding Next.js to an existing ESLint setup, spread the Next.js config into your array:

import nextConfig from 'eslint-config-next/core-web-vitals' // Your other config imports...   const eslintConfig = [  // Your other configurations...  ...nextConfig, ]   export default eslintConfig

When you spread ...nextConfig, you're adding multiple config objects that include file patterns, plugins, rules, ignores, and parser settings. ESLint applies configs in order, so later rules can override earlier ones for matching files.

Good to know: This approach works well for straightforward setups. If you have a complex existing config with specific file patterns or plugin configurations that conflict, consider using the plugin directly (as shown above) for more granular control.