Next.js 15.3, released by Vercel in April 2025, is a significant update aimed at improving build speed, developer experience, observability, and client-side navigation control. Whether you manage a large codebase, work on enterprise-grade projects, or focus on performance optimization, this release brings several features worth exploring.

 

In this post, we will cover:

 

 

By the end, you will have a clear understanding of the update and how it can benefit Healthcare, Fintech, and E-commerce projects.

 

 

 

Next.js 15.3 introduces several key updates. Let’s explore them in detail:

 

 

next build --turbopack

 

Turbopack scales efficiently with CPU cores:

 

• ~28% faster than Webpack on 4 cores

• ~60% faster on 16 cores

• ~83% faster on 30 cores

It now has high test coverage, with over 99% of next build integration tests passing under Turbopack.

 

 

Previously, Turbopack was configured under experimental.turbo in next.config.ts. In 15.3, it moved to a top-level turbopack key, simplifying setup.

 

 

 

Rspack is an adapter to allow compatibility with Webpack APIs while gaining some performance improvements. This is useful for teams that:

 

• Cannot migrate fully to Turbopack immediately

• Want faster builds without reworking their existing Webpack setup

The next-rspack plugin currently passes ~96% of Next.js integration tests.

 

 

 

You can now create an instrumentation-client.js or .ts file at the root of your project. This file executes before your application’s frontend code, allowing you to:

 

• Track analytics

• Monitor performance

• Catch early errors

This feature is particularly useful for high-traffic projects where capturing metrics from the very start improves observability and debugging.

 

 

 

Next.js 15.3 introduces enhanced client-side navigation controls.

 

 

 

• A React hook used in client components

• Returns a pending boolean indicating navigation progress

• Allows localized loading indicators for smoother UX

 

 

The Next.js TypeScript Language Server Plugin (LSP) has been made more efficient:

 

This makes large-scale TypeScript projects more productive and reliable.

 

 

 

Next.js 15.3 addresses key challenges in modern web development:

 

 

Turbopack in production builds reduces CI/CD times and improves iteration speed.

 

 

Rspack helps teams transition gradually from Webpack to Turbopack without breaking their builds.

 

 

useLinkStatus and onNavigate enhance client-side transitions and localized loading states.

 

 

Instrumentation hooks enable performance tracking and error logging from the very first millisecond.

 

 

Improved LSP ensures that developers working on large codebases experience less IDE lag and better error reporting.

 

 

 

npm install next@latest react@latest react-dom@latest
next build --turbopack

import type { NextConfig } from 'next'

const nextConfig: NextConfig = {
  turbopack: {
    rules: {
      '*.svg': {
        loaders: ['@svgr/webpack'],
        as: '*.js',
      },
    },
  },
}

export default nextConfig

 

// instrumentation-client.ts
performance.mark('app-init')
initAnalytics()

window.addEventListener('error', (event) => reportError(event.error))

This will capture performance metrics and errors before any app logic runs.

 

 

// A component with a Link that uses onNavigate
import Link from 'next/link'

function MyLink() {
  return (
    <Link href="/profile" onNavigate={(e) => {
      // maybe block navigation under certain conditions
      if (!userLoggedIn) {
        e.preventDefault()
        showLoginModal()
      }
    }}>
      Go to Profile
    </Link>
  )
}

// Using useLinkStatus in a client component
'use client'

import { useLinkStatus } from 'next/navigation'

export default function NavIndicator() {
  const { pending } = useLinkStatus()
  return pending ? <div>Loading...</div> : null
}

This example shows localized loading states and conditional navigation prevention.

5. TypeScript Plugin

 

Caveats, Gotchas & Community Feedback

 

Example: From Zero to Using New Features

 

npx create-next-app@latest next15-demo
cd next15-demo
npm install next@15.3 react@latest react-dom@latest

next.config.ts:

// next.config.ts
import type { NextConfig } from 'next'

const nextConfig: NextConfig = {
  turbopack: {
    rules: {
      '*.svg': {
        loaders: ['@svgr/webpack'],
        as: '*.js',
      },
    },
  },
}

Instrumentation file:

performance.mark('app-init')
initAnalytics()
window.addEventListener('error', (e) => reportError(e.error))

Client component navigation:

// components/Nav.tsx
'use client'

import { useLinkStatus } from 'next/navigation'
import Link from 'next/link'

export function Nav() {
  const { pending } = useLinkStatus()
  return (
    <div>
      {pending && <span>Loading route...</span>}
      <Link href="/about" onNavigate={(e) => {
        console.log('Navigating to about')
      }}>About</Link>
    </div>
  )
}

Build with Turbopack:

next build --turbopack

Test navigation, instrumentation, and LSP responsiveness.

What to Watch Next / Roadmap Implications

Conclusion

Ready to upgrade your web applications with Next.js 15.3 for faster builds, better UX, and full observability? Contact us today and let our experts help you implement these cutting-edge features.