Next.js App Router vs Pages Router: When to Use Which

Introduction

Next.js offers two routing systems: the traditional Pages Router and the modern App Router. Understanding the differences, advantages, and use cases for each is crucial for making informed decisions about which routing approach fits your project requirements. This guide will help you choose the right router for your needs.

Pages Router: The Traditional Approach

The Pages Router is Next.js's original routing system, based on file-based routing:

• File-based routing where each file in pages/ becomes a route
• Simple and straightforward for traditional React applications
• Well-established with extensive documentation and community support
• Compatible with most React libraries and patterns
• Uses getServerSideProps and getStaticProps for data fetching
• Supports API routes in pages/api/

App Router: The Modern Approach

The App Router is Next.js's new routing system introduced in version 13:

• Directory-based routing using the app/ directory
• Built-in support for React Server Components
• Advanced layouts and nested routing
• Improved data fetching with async Server Components
• Better loading and error states with special files
• Streaming and Suspense support

Key Differences

Routing Structure

• Pages Router: pages/about.js → /about
• App Router: app/about/page.js → /about

Data Fetching

• Pages Router: getServerSideProps, getStaticProps, getStaticPaths
• App Router: Direct async functions in Server Components

Layouts

• Pages Router: Custom _app.js and _document.js
• App Router: Built-in layout.js files at any level

When to Use Pages Router

Choose Pages Router when:

• Migrating existing Next.js applications
• Team is more familiar with traditional React patterns
• Project doesn't require Server Components features
• Using libraries that don't support App Router yet
• Building simple applications without complex routing needs

When to Use App Router

Choose App Router when:

• Starting a new project
• Need Server Components for better performance
• Require advanced layouts and nested routing
• Want streaming and Suspense features
• Building applications that benefit from React 18+ features

Migration Considerations

If migrating from Pages to App Router:

• Plan the migration carefully
• Test thoroughly in a staging environment
• Update data fetching patterns
• Refactor layouts and routing structure
• Update third-party library integrations

Conclusion

Both routing systems have their place in Next.js development. The Pages Router remains a solid choice for traditional applications, while the App Router offers modern features and better performance for new projects. Choose based on your project requirements, team expertise, and long-term goals.