# Route Segment Config in Next.js

# The Big Picture

* These are settings you export from your pages or layouts
    
* They are being replaced with more granular caching using dynamicIO
    
* They represent the "old way" of configuring pages all at once
    

# Code snippet

```javascript
// Route Segment Configuration Options
// These configs control how your page/layout behaves
// NOTE: These will be deprecated in favor of dynamicIO in the future

export default function Page() {
  return <div>My Page</div>;
}

// Enable Partial Prerendering (experimental)
// Mix static & dynamic content in same route
export const experimental_ppr = true;

// Control if page is static or dynamic
export const dynamic = "auto"; // Options:
// 'auto' - default, caches what it can
// 'force-dynamic' - everything dynamic/real-time
// 'error' - forces everything static, errors if dynamic
// 'force-static' - forces static, empty cookies/headers

// Handle dynamic routes not in generateStaticParams
export const dynamicParams = true; // Options:
// true - generate dynamic pages on demand (default)
// false - return 404 for undefined routes

// Set revalidation time for the route
export const revalidate = 60; // Options:
// false - cache indefinitely (default)
// 0 - never cache
// number - seconds to cache

// Choose runtime environment
export const runtime = "nodejs"; // Options:
// 'nodejs' - default, full Node.js features
// 'edge' - lighter, faster, fewer features

// Pick deployment region
export const preferredRegion = "auto"; // Options:
// 'auto' - platform decides (default)
// 'global' - deploy globally
// 'home' - home region
// ['iad1', 'sfo1'] - specific regions

// Set execution time limit
export const maxDuration = 5; // In seconds
```

# Key Options

## experimental\_ppr (boolean)

* WHAT: Enables Partial Prerendering for a route
    
* USE WHEN: You want to mix static and dynamic content
    
* AVOID WHEN: You're in production and worried it'll break things
    

## dynamic ('auto' | 'force-dynamic' | 'error' | 'force-static')

* WHAT: Controls if page is static or dynamic
    
* USE WHEN:
    
    * 'force-dynamic': Need real-time data for entire page
        
    * 'error': Must ensure everything is static
        
    * 'force-static': Need to force empty cookies/headers
        
* AVOID WHEN:
    
    * You can use granular fetch caching instead
        
    * Only parts of your page need to be dynamic (use PPR instead)
        

## dynamicParams (boolean)

* WHAT: Controls behavior for dynamic routes not in generateStaticParams
    
* USE WHEN: You want to generate dynamic pages on demand (true)
    
* AVOID WHEN: You want 404s for undefined routes (false)
    

## revalidate (false | 0 | number)

* WHAT: Sets default revalidation time
    
* USE WHEN:
    
    * Need consistent revalidation across page
        
    * Want to override fetch cache settings
        
* AVOID WHEN:
    
    * Using Edge runtime
        
    * Different parts need different revalidation times
        

## runtime ('nodejs' | 'edge')

* WHAT: Picks runtime environment
    
* USE WHEN: Need edge capabilities
    
* AVOID WHEN: Using Node.js specific features (stick to default)
    

## preferredRegion

* WHAT: Controls deployment region
    
* USE WHEN: Need specific regional deployment
    
* AVOID WHEN: Global deployment is fine (use 'auto')
    

## maxDuration

* WHAT: Sets execution time limits
    
* USE WHEN: Need to control server-side execution time
    
* AVOID WHEN: Standard timeouts are sufficient
    

# Important Note

These configs are part of the "old model" where you configure entire pages.

The future is moving toward:

* [Dynamic IO](https://nextjs.org/docs/app/api-reference/config/next-config-js/dynamicIO) for better performance
    
* More granular control with fetch-level caching
    
* Partial Prerendering for mixing static/dynamic content