Next.js 15.5: Key Features, Updates, What Developers Need to Know

Aug 25, 2025

When I first met Next.js 15.5…

I was midway through a project—juggling client-side routes, middleware quirks, and build times that felt like watching paint dry.
Then version 15.5 dropped, and I thought:

"okay, they might’ve actually read my mind."

Turns out, they did.

What landed in Next.js 15.5 (August 18, 2025)

Here’s what stood out to me, straight from the official release:

Turbopack production builds (beta) — next build --turbopack now works for production, already serving over 1.2B requests on nextjs.org.
Node.js middleware is stable — no more “edge-only” limits. Use fs, crypto, and npm packages in your middleware.
TypeScript improvements — typed routes, route export validation, and global PageProps/LayoutProps, plus a new next typegen command.
next lint is deprecated — moving forward, set up ESLint or Biome manually. next lint disappears in v16.
Heads-up for Next.js 16 — warnings for legacyBehavior, AMP, Image quality config, and local image patterns.

Why this matters for us

1. Turbopack in beta for real builds

I ran a next build --turbopack. Still not instant, but noticeably faster. Some projects already report 2–5× speed improvements. That’s time saved on every deployment.

2. Middleware that finally feels like middleware

Need to tap into the filesystem or generate crypto-secure tokens before a page renders? Now you can. Middleware runs in a full Node.js runtime—stability unlocked.

typescript

// middleware.ts
import { NextRequest, NextResponse } from 'next/server';
 
export const config = {
  runtime: 'nodejs', // Now stable!
};
 
export function middleware(request: NextRequest) {
  // Access to full Node.js APIs and npm packages
  const fs = require('fs');
  const crypto = require('crypto');
 
  // Complex authentication logic
  const token = request.headers.get('authorization');
 
  if (!isValidToken(token)) {
    return NextResponse.redirect(new URL('/login', request.url));
  }
 
  return NextResponse.next();
}
 
function isValidToken(token: string | null): boolean {
  // Use Node.js crypto for validation
  // Access file system, databases, etc.
  return true;
}

3. TypeScript just leveled up

Typed routes now work with both Webpack and Turbopack. Example: if you mistype <Link href="/dashboard">, the compiler warns before you hit save. next typegen also helps validate routes during CI.

typescript

// next.config.ts

const nextConfig = {
  typedRoutes: true, // Now stable!
  // Other code
};
 
export default nextConfig;

4. Clarity on what’s going away

No more upgrade-day headaches. You’ll see dev warnings for deprecated features so you can fix them before v16 ships.

A quick real-world example

I refactored a project with type-safe links and middleware that authenticates users using crypto-hashed tokens stored in a file.
It felt natural—not a hack. And I caught a broken route before it hit staging. Small wins that add up.

What you can do right now

Try --turbopack for faster builds.
Start using Node.js middleware.
Enable typedRoutes in next.config.ts.
Move to ESLint or Biome CLI (say goodbye to next lint).
Clean up legacy props and AMP before v16.

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For more informations, go to the official doc Next.js 15.5