Redirect and rewrite in middleware in NextJS

Introduction

Redirects and rewrites help you send users to different pages or change the URL behind the scenes. Middleware lets you do this before the page loads.

Send users to a login page if they are not signed in.

Change old URLs to new ones without breaking links.

Redirect users based on their location or device type.

Rewrite URLs to hide complex query parameters.

Protect pages by redirecting unauthorized users.

Syntax

NextJS

import { NextResponse } from 'next/server';

export function middleware(request) {
  // Redirect example
  if (request.nextUrl.pathname === '/old-path') {
    return NextResponse.redirect(new URL('/new-path', request.url));
  }

  // Rewrite example
  if (request.nextUrl.pathname === '/about') {
    return NextResponse.rewrite(new URL('/company-info', request.url));
  }

  return NextResponse.next();
}

Use NextResponse.redirect() to send users to a different URL.

Use NextResponse.rewrite() to change the URL internally without changing what the user sees.

Examples

This sends the user to the login page.

NextJS

return NextResponse.redirect(new URL('/login', request.url));

This shows the dashboard page but keeps the original URL in the browser.

NextJS

return NextResponse.rewrite(new URL('/dashboard', request.url));

Redirects from '/old' to '/new'.

NextJS

if (request.nextUrl.pathname === '/old') {
  return NextResponse.redirect(new URL('/new', request.url));
}

Rewrites '/profile' to '/user/profile' internally.

NextJS

if (request.nextUrl.pathname === '/profile') {
  return NextResponse.rewrite(new URL('/user/profile', request.url));
}

Sample Program

This middleware redirects anyone visiting '/home' to '/dashboard'. It also rewrites '/info' to show the content of '/about-us' without changing the URL in the browser.

NextJS

import { NextResponse } from 'next/server';

export function middleware(request) {
  const { pathname } = request.nextUrl;

  // Redirect users from /home to /dashboard
  if (pathname === '/home') {
    return NextResponse.redirect(new URL('/dashboard', request.url));
  }

  // Rewrite /info to /about-us internally
  if (pathname === '/info') {
    return NextResponse.rewrite(new URL('/about-us', request.url));
  }

  // Continue normally for other paths
  return NextResponse.next();
}

Important Notes

Redirect changes the URL the user sees and sends them to a new page.

Rewrite changes the page content behind the scenes but keeps the URL the same.

Middleware runs before the page loads, so it is good for quick checks and changes.

Summary

Use NextResponse.redirect() to send users to a new URL.

Use NextResponse.rewrite() to change the page content without changing the URL.

Middleware lets you control routing before the page loads.

Practice

1. What is the main difference between a redirect and a rewrite in Next.js middleware?

easy

A. Rewrite changes the URL in the browser, redirect does not.

B. Redirect changes the URL in the browser, rewrite does not.

C. Redirect and rewrite both change the URL in the browser.

D. Neither redirect nor rewrite affect the URL in the browser.

Solution

1. Step 1: Understand redirect behavior

   A redirect sends the user to a new URL and updates the browser's address bar to that URL.

2. Step 2: Understand rewrite behavior

   A rewrite changes the content served without changing the URL shown in the browser.

3. Final Answer:

   Redirect changes the URL in the browser, rewrite does not. -> Option B

4. Quick Check:

   Redirect updates URL, rewrite keeps URL same [OK]

Hint: Redirect changes URL; rewrite keeps URL same [OK]

Common Mistakes:

• Thinking rewrite changes browser URL
• Confusing redirect with rewrite
• Assuming both always change URL

2. Which of the following is the correct way to perform a redirect in Next.js middleware?

easy

A. return NextResponse.redirect('/home');

B. return NextResponse.rewrite(new URL('/home', request.url));

C. return NextResponse.next('/home');

D. return NextResponse.redirect(new URL('/home', request.url));

Solution

1. Step 1: Check NextResponse.redirect syntax

   The redirect method requires a full URL object, created with new URL(path, base).

2. Step 2: Validate options

   return NextResponse.redirect(new URL('/home', request.url)); correctly uses new URL with request.url as base. return NextResponse.redirect('/home'); incorrectly passes a string instead of URL object.

3. Final Answer:

   return NextResponse.redirect(new URL('/home', request.url)); -> Option D

4. Quick Check:

   Redirect needs URL object [OK]

Hint: Use new URL(path, request.url) for redirects [OK]

Common Mistakes:

• Passing string directly to redirect
• Using rewrite instead of redirect
• Missing base URL in new URL()

3. Given this middleware code snippet, what will happen when a user visits '/dashboard'?

import { NextResponse } from 'next/server';
export function middleware(request) {
  if (request.nextUrl.pathname === '/dashboard') {
    return NextResponse.rewrite(new URL('/profile', request.url));
  }
  return NextResponse.next();
}

medium

A. User sees content from '/profile' but URL stays '/dashboard'.

B. User is redirected to '/profile' and URL changes.

C. User stays on '/dashboard' with original content.

D. Middleware throws an error due to incorrect syntax.

Solution

1. Step 1: Analyze rewrite usage

   The code uses NextResponse.rewrite to serve '/profile' content when URL is '/dashboard'.

2. Step 2: Understand rewrite effect on URL

   Rewrite changes content served but keeps the browser URL unchanged as '/dashboard'.

3. Final Answer:

   User sees content from '/profile' but URL stays '/dashboard'. -> Option A

4. Quick Check:

   Rewrite changes content, not URL [OK]

Hint: Rewrite serves new content but keeps URL same [OK]

Common Mistakes:

• Confusing rewrite with redirect
• Expecting URL to change on rewrite
• Assuming middleware throws error here

4. Identify the error in this middleware code that tries to redirect users from '/old' to '/new':

import { NextResponse } from 'next/server';
export function middleware(request) {
  if (request.nextUrl.pathname === '/old') {
    return NextResponse.redirect('/new');
  }
  return NextResponse.next();
}

medium

A. The condition should check request.url, not request.nextUrl.pathname.

B. Middleware must be async to use redirect.

C. Redirect requires a full URL object, not a string.

D. NextResponse.next() cannot be returned in middleware.

Solution

1. Step 1: Check redirect argument type

   NextResponse.redirect expects a URL object, not a string path.

2. Step 2: Validate other parts

   Condition and NextResponse.next() usage are correct; async not required here.

3. Final Answer:

   Redirect requires a full URL object, not a string. -> Option C

4. Quick Check:

   Redirect needs URL object, not string [OK]

Hint: Redirect needs new URL(path, request.url) [OK]

Common Mistakes:

• Passing string directly to redirect
• Making middleware async unnecessarily
• Checking wrong request property

5. You want to redirect users to '/login' if they visit any page except '/public' or '/login'. Which middleware code correctly implements this logic?

hard

A. if (!['/public', '/login'].includes(request.nextUrl.pathname)) {
return NextResponse.redirect(new URL('/login', request.url));
}
return NextResponse.next();

B. if (['/public', '/login'].includes(request.nextUrl.pathname)) {
return NextResponse.redirect(new URL('/login', request.url));
}
return NextResponse.next();

C. if (request.nextUrl.pathname !== '/public' || request.nextUrl.pathname !== '/login') {
return NextResponse.redirect(new URL('/login', request.url));
}
return NextResponse.next();

D. if (request.nextUrl.pathname === '/public' && request.nextUrl.pathname === '/login') {
return NextResponse.redirect(new URL('/login', request.url));
}
return NextResponse.next();

Solution

1. Step 1: Understand condition logic

   We want to redirect if the path is NOT '/public' or '/login'. Using !includes checks this correctly.

2. Step 2: Check each option's condition

   if (!['/public', '/login'].includes(request.nextUrl.pathname)) { return NextResponse.redirect(new URL('/login', request.url)); } return NextResponse.next(); correctly uses negation with includes. if (['/public', '/login'].includes(request.nextUrl.pathname)) { return NextResponse.redirect(new URL('/login', request.url)); } return NextResponse.next(); redirects only on '/public' or '/login' which is wrong. Options C and D have logical errors in conditions.

3. Final Answer:

   Option A code correctly redirects except for '/public' and '/login'. -> Option A

4. Quick Check:

   Use !includes for exclusion check [OK]

Hint: Use !includes to exclude paths for redirect [OK]

Common Mistakes:

• Using OR instead of AND in conditions
• Redirecting on allowed paths
• Incorrect logical negation