Next.js Routing Explained: App Router vs Pages Router in 2025

Introduction

Next.js, that amazing React framework we all use for building fast web apps, hasn't stopped evolving since it first appeared. Fast forward to 2025, and the App Router, which came out a few years ago, is now the dominant way to handle routing in Next.js. Still, you'll find the older Pages Router hanging around in a lot of projects, especially ones that are slowly being updated. If you're a Next.js developer in 2025, it's super important to know the ins and outs of both these routing systems. So, in this article, we'll dive deep into the App Router and the Pages Router, looking at what they offer, how they're different, and when you might want to use each one.

A Quick Look Back at Next.js Routing

Before we get into the details, let's quickly remember how Next.js routing used to work. At first, Next.js only had the Pages Router. This system used your file structure to create routes. Basically, any file in the pages directory automatically became a route based on its name. It was easy to understand, but the Pages Router wasn't that great when it came to things like getting data, organizing components, and just being flexible overall, especially as apps got bigger.

Then came the App Router, which changed everything. It introduced a new app directory where you could build routes using React Server Components, Streaming, and more advanced ways to fetch data. The App Router was designed to be more powerful and flexible for building modern web apps, fixing the problems of the Pages Router. Now in 2025, the App Router is the way to go for new Next.js projects, but you can still use the Pages Router if you want to update your project bit by bit.

The Pages Router: The Old Reliable

The Pages Router, which you'll find in the pages directory, is still a decent choice, especially for smaller projects or parts of bigger apps. Here's what you need to know about it:

• File-System Based Routing: This is the main idea behind the Pages Router. It turns files directly into routes. So, a file called about.js in the pages directory automatically creates a route at /about. For routes that change, you use brackets like [id].js, where id becomes a parameter you can access with useRouter.

• Smooth Navigation with next/link: The next/link component lets you jump between pages without reloading the whole page, which makes things feel faster.

• Ways to Get Data: The Pages Router gives you a few options for fetching data:

  • getStaticProps: Gets data when you build your app, perfect for content that doesn't change much.
  • getServerSideProps: Gets data every time someone visits the page, good for content that needs to be up-to-date.
  • getInitialProps: An older way to fetch data on both the client and server, but it's usually better to use getStaticProps and getServerSideProps instead.

• React Client Components: Pages in the pages directory are React Client Components by default. That means they run in the browser and can use browser features.

Here's an example of a page in the Pages Router:

// pages/about.js
import Link from 'next/link';

function AboutPage() {
  return (
    <div>
      <h1>About Us</h1>
      <p>This is the about page.</p>
      <Link href="/">
        <a>Go to Home</a>
      </Link>
    </div>
  );
}

export default AboutPage;

What's good about the Pages Router:

• Simple: The file-based routing is easy to pick up.
• Mature: It's been around for a while, so there's lots of help and documentation available.
• Easy to Update: You can use both the App Router and the Pages Router in the same project, making it easy to switch over gradually.

What's not so good about the Pages Router:

• Not very Flexible: The file-based routing can be limiting for more complex websites.
• Relies on Client-Side Rendering: Tends to use client-side rendering, which can make the initial page load slower.
• Tricky Data Fetching: Managing complicated data can be a hassle.

The App Router: Embracing the Future of Web Development

The App Router, which lives in the app directory, is a big step forward in Next.js routing. It uses React Server Components and Streaming to give you a more powerful and flexible way to build websites.

• Directory-Based Routing: Like the Pages Router, the App Router uses your directory structure to create routes. Each directory in the app directory represents a part of the route. A page.js file inside a directory defines the route itself.

• React Server Components (RSCs): This is what makes the App Router special. Components in the app directory are React Server Components by default. RSCs run on the server, so you can fetch data and render things on the server before sending HTML to the client. This makes the initial page load much faster and improves SEO.

• Client Components: Even though RSCs are the default, you can still use Client Components in the app directory. Just add the "use client" directive at the top of the file to tell Next.js it's a Client Component.

• Fetching Data with fetch: The App Router encourages you to use the fetch API for getting data. The fetch API has been updated with Next.js-specific features, like automatic request deduplication and caching.

• Streaming: The App Router supports streaming, which means you can show different parts of a page as the data becomes available. This makes the user experience better by giving faster feedback.

• Layouts: Layouts let you create shared UI elements that stay the same across multiple pages. You define them in a layout.js file inside a directory.

• Route Groups: Route groups let you organize your routes without changing the URL structure. Just put the directory name in parentheses, like (marketing)/about/page.js, which will be accessible at /about.

Here's an example of a page in the App Router:

// app/about/page.js
export default async function AboutPage() {
  const data = await fetchData(); // Fetch data on the server
  return (
    <div>
      <h1>About Us</h1>
      <p>This is the about page with data: {data.message}</p>
    </div>
  );
}

async function fetchData() {
  const res = await fetch('https://api.example.com/about');
  return res.json();
}

Here's an example of a Client Component in the App Router:

// app/components/Counter.js
"use client";

import { useState } from 'react';

export default function Counter() {
  const [count, setCount] = useState(0);

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

What's great about the App Router:

• Faster Performance: React Server Components and Streaming make the initial page load much faster and improve SEO.
• More Flexible: The directory-based routing and layout system give you more control over complex websites.
• Better Data Handling: The fetch API with built-in caching and request deduplication makes it easier to manage data.
• Modern Architecture: Uses the latest React features and best practices.

What's not so great about the App Router:

• More Complex: React Server Components and Streaming can be tricky to understand at first.
• Learning Curve: You'll need to learn a new way of building Next.js apps.
• Still Evolving: The App Router is improving quickly, but the tools and support around it are still catching up to the Pages Router.

App Router vs. Pages Router: A Detailed Look in 2025

Here's a table that sums up the key differences between the App Router and the Pages Router in 2025:

| Feature | Pages Router | App Router | | ----------------- | ------------------------------------------------ | --------------------------------------------------------------------------------------------------------- | | Location | pages directory | app directory | | Routing | File-system based | Directory-based | | Component Type | React Client Components (by default) | React Server Components (by default), Client Components (with "use client") | | Data Fetching | getStaticProps, getServerSideProps, getInitialProps | fetch API with caching and deduplication, server-side data fetching directly within components | | Rendering | Primarily Client-Side Rendering | Server-Side Rendering (with RSCs), Streaming | | Layouts | Custom implementations required | Built-in Layout system | | Error Handling | Custom implementations required | Built-in Error handling with error boundary components | | Code Organization | Less structured | More structured with directories and layouts | | Performance | Can be slower due to client-side rendering | Generally faster due to server-side rendering and streaming | | SEO | Requires optimization techniques | Improved out-of-the-box due to server-side rendering | | Complexity | Simpler to understand and implement | More complex due to the introduction of RSCs and Streaming |

How to Move From Pages to App

Moving from the Pages Router to the App Router can be tricky, especially for big apps. Here are some things to keep in mind:

• Update Gradually: Start by moving one page or section at a time. This lets you get used to the new features and fix any problems along the way.
• Use App Router for New Stuff: Build all new features with the App Router while keeping the Pages Router for the older parts of your app.
• Move Components First: Update individual components to React Server Components and then slowly add them to the App Router.
• Run Both Versions Together: Run both the Pages Router and App Router versions of your app at the same time and slowly send people to the App Router version.

Things to think about when updating:

• How You Get Data: Re-think how you get data to take advantage of the fetch API and server-side data fetching.
• How Your Components Are Organized: Re-organize your components to use React Server Components and Client Components effectively.
• How You Manage State: Think about how state management tools like Redux or Zustand will work with React Server Components.
• Are Your Libraries Compatible?: Make sure any libraries you're using work with React Server Components.

The Future of Next.js Routing (Looking Ahead to 2025 and Beyond)

After 2025, the App Router will likely be the main way to handle routing in Next.js. We can expect to see even more improvements in areas like:

• Easier to Use: More tools and better documentation to make it easier to work with React Server Components and Streaming.
• Smarter Data Fetching: New and improved ways to fetch data, like data mutations and optimistic updates.
• Better Streaming: Even more control over how things are rendered with more granular streaming.
• AI Integration: Integration with AI tools for writing code, fixing bugs, and improving performance.
• Easier Serverless Deployment: Simpler and cheaper ways to deploy your app using serverless functions.

In Conclusion

By 2025, understanding the differences between the App Router and the Pages Router is a must for any Next.js developer. While the Pages Router is still a good choice for simple projects or for updating your app gradually, the App Router is the future of Next.js routing. By using React Server Components, Streaming, and advanced data fetching, the App Router lets you build web apps that are faster, more scalable, and easier to maintain. The Next.js ecosystem will continue to evolve, so staying up-to-date with the latest routing trends and best practices is key to building amazing web experiences. It might take some time to learn the new concepts, but the long-term benefits in terms of performance, flexibility, and maintainability make it worth the effort.