---
title: "How it works"
description: "Learn how the Nuxt Site Config module works, so you can get the most out of it."
canonical_url: "https://nuxtseo.com/docs/site-config/guides/how-it-works"
last_updated: "2026-05-12T14:10:04.017Z"
---

# Config Sources

Site config resolves from the following sources, in order of precedence:

## Build Time

### 1. System

System details relate to the environment the app is running in.

```ts
export default {
  env: process.env.NODE_ENV,
}
```

The `indexable` property is not set directly in the system config. It is derived at read time from `env` by the `getSiteIndexable()` utility, which defaults to `true` when `env` is `'production'`.

### 2. Vendor CI Environment

When deploying to supported platforms, `url` and `name` are automatically populated from platform environment variables. These have low priority and are overridden by any explicit config you provide.

<table>
<thead>
  <tr>
    <th>
      Platform
    </th>
    
    <th>
      <code>
        url
      </code>
    </th>
    
    <th>
      <code>
        name
      </code>
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <a href="https://vercel.com" rel="nofollow">
        Vercel
      </a>
    </td>
    
    <td>
      <code>
        VERCEL_URL
      </code>
      
      , <code>
        NUXT_ENV_VERCEL_URL
      </code>
    </td>
    
    <td>
      <code>
        NUXT_ENV_VERCEL_GIT_REPO_SLUG
      </code>
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="https://netlify.com" rel="nofollow">
        Netlify
      </a>
    </td>
    
    <td>
      <code>
        URL
      </code>
    </td>
    
    <td>
      <code>
        SITE_NAME
      </code>
    </td>
  </tr>
  
  <tr>
    <td>
      Cloudflare Pages
    </td>
    
    <td>
      <code>
        CF_PAGES_URL
      </code>
    </td>
    
    <td>
      
    </td>
  </tr>
</tbody>
</table>

<note>

As of v4, `site.name` is no longer inferred from your project directory or `package.json`. It will only be auto-populated from CI platform env vars listed above, or from explicit config. See the [v4 release notes](/docs/site-config/releases/v4).

</note>

### 3. Module overrides

Build time site config provided by modules.

### 4. Nuxt Config `site` key

Site config provided by the user in the Nuxt config.

### 5. Runtime Config and Environment Variables

Site config provided by the user at runtime. `runtimeConfig.public.site` and associated environment variables (e.g. `NUXT_SITE_URL`, `NUXT_SITE_NAME`).

### 6. Nuxt Hook

The `site-config:resolve` hook fires to allow any final build time modifications to the config.

## SSR / Nitro Runtime

### 1. Request URL

The request URL determines the site URL at runtime.

### 2. Build Time Site Config

Config resolved in the build step, stored on `runtimeConfig['nuxt-site-config'].stack`.

### 3. Route Rules

Config resolved from the route rules of the request path, the `site` key. This allows for multi-site support.

## CSR Runtime

In CSR, site config is not re-derived from the browser context. Instead, it is hydrated directly from the SSR-rendered payload sent by the server. This ensures the client has the same config as the server without any hydration mismatches.