---
title: "Next.js 15 and the App Router: A Complete Migration Guide"
description: "Complete guide to migrating from Next.js Pages Router to App Router with step-by-step instructions and Next.js 15 features overview."
canonical: https://itsupportintokyo.com/en/blog/nextjs-15-app-router-guide
language: en-US
published: 2026-02-04T15:29:13.428Z
modified: 2026-04-28T07:38:15.698Z
author: "IT Support Tokyo"
keywords: "Next.js, App Router, React Server Components, web development, migration"
image: https://izdteczidppwfupoddun.supabase.co/storage/v1/object/public/blog-images/blog-nextjs-app-router.jpg
translation: https://itsupportintokyo.com/ja/blog/nextjs-15-app-router-guide
---

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

> Complete guide to migrating from Next.js Pages Router to App Router with step-by-step instructions and Next.js 15 features overview.

## 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

- **Audit Your App**: Identify pages and API routes
- **Set Up App Directory**: Create parallel structure
- **Convert Layouts**: Create layout.tsx files
- **Migrate Pages**: Convert to Server Components
- **Update Data Fetching**: Replace getServerSideProps with async components
- **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

## Source

Canonical HTML: https://itsupportintokyo.com/en/blog/nextjs-15-app-router-guide
Other language: https://itsupportintokyo.com/ja/blog/nextjs-15-app-router-guide