vercel__next.js/errors/prerender-error.mdx

---
title: Prerender Error with Next.js
---

## Why This Error Occurred

While prerendering a page during `next build`, an error occurred. This can happen for various reasons, including:

1. Incorrect file structure or non-page files in the `pages/` directory
2. Expecting props to be populated which are not available during prerendering
3. Using browser-only APIs in components without proper checks
4. Incorrect configuration in `getStaticProps` or `getStaticPaths`

## Possible Ways to Fix It

### 1. Ensure correct file structure and use App Router for colocation

#### Pages Router

In the Pages Router, only special files are allowed to generate pages. You cannot colocate other files (e.g., components, styles) within the `pages` directory.

Correct structure:

```txt
  .
  ├── components/
  │   └── Header.js
  ├── pages/
  │   ├── about.js
  │   └── index.js
  └── styles/
      └── globals.css
```

#### App Router (Next.js 13+)

The App Router allows [colocation](/docs/app/getting-started/project-structure#colocation) of pages and other files in the same folder. This provides a more intuitive project structure.

Example folder structure:

```txt
  .
  └── app/
      ├── about/
      │   └── page.tsx
      ├── blog/
      │   ├── page.tsx
      │   └── PostCard.tsx
      ├── layout.tsx
      └── page.tsx
```

### 2. Handle undefined props and missing data

#### Pages Router

For the Pages Router, use conditional checks and return appropriate props or a 404 page:

```jsx
export async function getStaticProps(context) {
  const data = await fetchData(context.params.id)
  if (!data) {
    return {
      notFound: true,
    }
  }
  return {
    props: { data },
  }
}
```

### 3. Handle fallback in dynamic routes

If you're using `fallback: true` or `fallback: 'blocking'` in `getStaticPaths`, ensure your page component can handle the loading state:

```jsx
import { useRouter } from 'next/router'

function Post({ post }) {
  const router = useRouter()

  if (router.isFallback) {
    return <div>Loading...</div>
  }

  return (
    <article>
      <h1>{post.title}</h1>
      <p>{post.content}</p>
    </article>
  )
}
```

### 4. Avoid exporting pages with server-side rendering

If you're using `next export` or `output: 'export'` in your `next.config.js`, ensure that none of your pages use `getServerSideProps`. Instead, use `getStaticProps` for data fetching:

```jsx
export async function getStaticProps() {
  const res = await fetch('https://api.vercel.app/blog')
  const data = await res.json()

  return {
    props: { data },
    revalidate: 60,
  }
}
```

### 5. Disable server-side rendering for components using browser APIs

If a component relies on browser-only APIs like `window`, you can disable server-side rendering for that component:

```jsx
import dynamic from 'next/dynamic'

const DynamicComponentWithNoSSR = dynamic(
  () => import('../components/BrowserOnlyComponent'),
  { ssr: false }
)

export default function Page() {
  return (
    <div>
      <h1>My page</h1>
      <DynamicComponentWithNoSSR />
    </div>
  )
}
```

## Debugging

For additional debugging information when troubleshooting prerender errors, you can run:

```bash
next build --debug-prerender
```

This provides unminified stack traces with source maps, making it easier to pinpoint the exact component and route causing the issue.

## Additional Resources

- [Handling Errors in Next.js](/docs/app/getting-started/error-handling)
- [Data Fetching in Next.js](/docs/app/getting-started/fetching-data)
- [Debugging prerender errors](/docs/app/api-reference/cli/next#debugging-prerender-errors)

If you continue to experience issues after trying these solutions, consider checking your server logs for more detailed error messages or reaching out to the Next.js community for support.