Next.js 15 App Router migration guide for modern React websites and web applications

Next.js 15 and the App Router: A Complete Migration Guide

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Key takeaways

Step-by-step guide to migrating from Next.js Pages Router to the App Router and leveraging new features in Next.js 15.

Why Migrate to App Router?

Next.js 15 with the App Router represents a fundamental shift in how we build React applications, offering improved performance, simplified data fetching, and better developer experience.

Key Benefits

  • React Server Components: Reduce client-side JavaScript
  • Streaming: Progressive page rendering
  • Simplified Data Fetching: No more getServerSideProps
  • Improved Caching: Built-in request memoization
  • Parallel Routes: Complex layouts made simple

Migration Steps

  1. Audit Your App: Identify pages and API routes
  2. Set Up App Directory: Create parallel structure
  3. Convert Layouts: Create layout.tsx files
  4. Migrate Pages: Convert to Server Components
  5. Update Data Fetching: Replace getServerSideProps with async components
  6. Handle Client Interactivity: Add 'use client' where needed

Next.js 15 New Features

  • Turbopack for development (stable)
  • Partial Prerendering (experimental)
  • Improved TypeScript support
  • Enhanced security headers