Next.js 15 RC: Features, Comparisons, and Code Examples

Introduction

The release of Next.js 15 RC marks another milestone for the React-based framework, delivering innovations in routing, API handling, image optimization, caching, and development tooling. With this version, Next.js focuses on improving flexibility, scalability, and performance, addressing the needs of both small projects and enterprise-scale applications.

1. Enhanced Routing System

The routing system in Next.js 15 has been enhanced with support for nested layouts, parallel routes, and route groups. Nested layouts allow developers to define reusable layouts at various levels of the application, improving code organization and scalability.

Parallel routes allow different sections of the page to load concurrently, improving performance and reducing load times. For example, a sidebar and main content can be fetched simultaneously, ensuring users see content faster.

// app/layout.js
export default function RootLayout({ children }) {
  return (



Sidebar Content

        {children}


  );
}

// app/page.js
export default function Page() {
  return 
Main Content
;
}

2. Edge API Routes

With Next.js 15, API routes can now run on Vercel’s Edge Network, ensuring lightning-fast responses and global scalability. These Edge API routes are particularly useful for latency-sensitive applications like e-commerce or streaming platforms.

export const config = { runtime: 'edge' };

export default async function handler(req) {
  return new Response(JSON.stringify({ message: 'Hello from the Edge!' }), {
    headers: { 'Content-Type': 'application/json' },
  });
}

3. Advanced Caching Control

Caching behavior has been redefined in Next.js 15. By default, fetch requests, route handlers, and client router caches are uncached, ensuring dynamic content remains up-to-date. Developers can explicitly define caching strategies based on their use case.

Example of specifying a caching strategy:

const data = await fetch('https://api.example.com/data', { cache: 'force-cache' });

1. Turbopack Stability

Turbopack, the successor to Webpack introduced in earlier versions, is now stable in Next.js 15. It significantly reduces build times and improves refresh rates, making the development process smoother and more efficient.

Activate Turbopack when creating a new Next.js project:
npx create-next-app@latest my-app --turbo

Feature Comparison: Next.js 14 vs Next.js 15

Feature | Next.js 14 | Next.js 15 RC

Routing | Basic Routing | Nested Layouts, Parallel Routes

Streaming | Partial Streaming | Automatic Streaming

Caching | Cached by Default | Uncached by Default

Conclusion

Next.js 15 RC builds upon the robust foundation of previous versions, introducing critical enhancements that make development faster, applications more performant, and user experiences smoother. Whether you are building a small personal project or a large-scale enterprise app, the innovations in this version offer something for everyone.