What's New in Next.js 15: A Complete Guide

Next.js 15 brings significant improvements to the React framework that powers millions of websites. In this comprehensive guide, we'll explore the most impactful changes and how they can benefit your projects.

Turbopack: Now Stable

Turbopack, the Rust-based successor to Webpack, is now stable in Next.js 15. This means faster build times and improved development experience:

• Up to 10x faster cold starts
• Incremental compilation for instant hot module replacement
• Better memory efficiency for large projects

React Compiler Support

Next.js 15 includes stable support for the React Compiler, which automatically optimizes your React code:

• Automatic memoization of components
• Reduced re-renders without manual optimization
• Better performance out of the box

Improved Caching APIs

The new caching system provides more explicit control over data caching:

• `revalidateTag()` now requires a cacheLife profile
• New `updateTag()` API for Server Actions
• `refresh()` for refreshing uncached data

Cache Components

The new "use cache" directive makes caching explicit and flexible:

'use cache'

export default async function Page() {
  const data = await fetchData()
  return <Component data={data} />
}

Getting Started

To upgrade to Next.js 15, simply update your dependencies and follow the migration guide for any breaking changes.