By default, Nuxt is configured to cover most use cases. The nuxt.config.ts file can override or extend this default configuration.
The nuxt.config.ts file is located at the root of a Nuxt project and can override or extend the application's behavior.
A minimal configuration file exports the defineNuxtConfig function containing an object with your configuration. The defineNuxtConfig helper is globally available without import.
export default defineNuxtConfig({
  // My Nuxt config
})
This file will often be mentioned in the documentation, for example to add custom scripts, register modules or change rendering modes.
.ts extension for the nuxt.config file. This way you can benefit from hints in your IDE to avoid typos and mistakes while editing your configuration.You can configure fully typed, per-environment overrides in your nuxt.config
export default defineNuxtConfig({
  $production: {
    routeRules: {
      '/**': { isr: true },
    },
  },
  $development: {
    //
  },
  $env: {
    staging: {
      //
    },
  },
})
To select an environment when running a Nuxt CLI command, simply pass the name to the --envName flag, like so: nuxt build --envName staging.
To learn more about the mechanism behind these overrides, please refer to the c12 documentation on environment-specific configuration.
$meta key to provide metadata that you or the consumers of your layer might use.The runtimeConfig API exposes values like environment variables to the rest of your application. By default, these keys are only available server-side. The keys within runtimeConfig.public and runtimeConfig.app (which is used by Nuxt internally) are also available client-side.
Those values should be defined in nuxt.config and can be overridden using environment variables.
export default defineNuxtConfig({
  runtimeConfig: {
    // The private keys which are only available server-side
    apiSecret: '123',
    // Keys within public are also exposed client-side
    public: {
      apiBase: '/api',
    },
  },
})
# This will override the value of apiSecret
NUXT_API_SECRET=api_secret_token
These variables are exposed to the rest of your application using the useRuntimeConfig() composable.
<script setup lang="ts">
const runtimeConfig = useRuntimeConfig()
</script>
The app.config.ts file, located in the source directory (by default the root of the project), is used to expose public variables that can be determined at build time. Contrary to the runtimeConfig option, these cannot be overridden using environment variables.
A minimal configuration file exports the defineAppConfig function containing an object with your configuration. The defineAppConfig helper is globally available without import.
export default defineAppConfig({
  title: 'Hello Nuxt',
  theme: {
    dark: true,
    colors: {
      primary: '#ff0000',
    },
  },
})
These variables are exposed to the rest of your application using the useAppConfig composable.
<script setup lang="ts">
const appConfig = useAppConfig()
</script>
runtimeConfig vs. app.configAs stated above, runtimeConfig and app.config are both used to expose variables to the rest of your application. To determine whether you should use one or the other, here are some guidelines:
runtimeConfig: Private or public tokens that need to be specified after build using environment variables.app.config: Public tokens that are determined at build time, website configuration such as theme variant, title and any project config that are not sensitive.| Feature | runtimeConfig | app.config | 
|---|---|---|
| Client Side | Hydrated | Bundled | 
| Environment Variables | ✅ Yes | ❌ No | 
| Reactive | ✅ Yes | ✅ Yes | 
| Types support | ✅ Partial | ✅ Yes | 
| Configuration per Request | ❌ No | ✅ Yes | 
| Hot Module Replacement | ❌ No | ✅ Yes | 
| Non primitive JS types | ❌ No | ✅ Yes | 
Nuxt uses nuxt.config.ts file as the single source of truth for configurations and skips reading external configuration files. During the course of building your project, you may have a need to configure those. The following table highlights common configurations and, where applicable, how they can be configured with Nuxt.
| Name | Config File | How To Configure | 
|---|---|---|
| Nitro | nitro.config.ts | Use nitrokey innuxt.config | 
| PostCSS | postcss.config.js | Use postcsskey innuxt.config | 
| Vite | vite.config.ts | Use vitekey innuxt.config | 
| webpack | webpack.config.ts | Use webpackkey innuxt.config | 
Here is a list of other common config files:
| Name | Config File | How To Configure | 
|---|---|---|
| TypeScript | tsconfig.json | More Info | 
| ESLint | eslint.config.js | More Info | 
| Prettier | prettier.config.js | More Info | 
| Stylelint | stylelint.config.js | More Info | 
| TailwindCSS | tailwind.config.js | More Info | 
| Vitest | vitest.config.ts | More Info | 
If you need to pass options to @vitejs/plugin-vue or @vitejs/plugin-vue-jsx, you can do this in your nuxt.config file.
vite.vue for @vitejs/plugin-vue. Check available options.vite.vueJsx for @vitejs/plugin-vue-jsx. Check available options.export default defineNuxtConfig({
  vite: {
    vue: {
      customElement: true,
    },
    vueJsx: {
      mergeProps: true,
    },
  },
})
If you use webpack and need to configure vue-loader, you can do this using webpack.loaders.vue key inside your nuxt.config file. The available options are defined here.
export default defineNuxtConfig({
  webpack: {
    loaders: {
      vue: {
        hotReload: true,
      },
    },
  },
})
You may need to enable experimental features in Vue, such as propsDestructure. Nuxt provides an easy way to do that in nuxt.config.ts, no matter which builder you are using:
export default defineNuxtConfig({
  vue: {
    propsDestructure: true,
  },
})
reactivityTransform migration from Vue 3.4 and Nuxt 3.9Since Nuxt 3.9 and Vue 3.4, reactivityTransform has been moved from Vue to Vue Macros which has a Nuxt integration.