Why Multiple root layouts with route groups in NextJS? - Purpose & Use Cases

The Big Idea

Discover how to effortlessly manage different page designs in one Next.js app without messy code!

The Scenario

Imagine building a website where different sections need completely different page structures, like a blog with one style and a shop with another, but you try to manage all layouts manually in each page.

The Problem

Manually repeating layout code on every page is tiring, error-prone, and makes updates a nightmare because you must change many files instead of one.

The Solution

Next.js lets you define multiple root layouts grouped by routes, so each section can have its own layout automatically applied, keeping your code clean and easy to maintain.

Before vs After

✗ Before

function BlogPage() { return <div><header>Blog Header</header><main>Content</main></div> }
function ShopPage() { return <div><header>Shop Header</header><main>Content</main></div> }

✓ After

app/(blog)/layout.js exports BlogLayout
app/(shop)/layout.js exports ShopLayout
Each page inside uses its group layout automatically

What It Enables

This makes it easy to build large apps with distinct sections, each having its own look and feel, without repeating code.

Real Life Example

A website with a marketing homepage, a user dashboard, and a blog, each with unique navigation and styles, all managed cleanly with route group layouts.

Key Takeaways

Manual layout repetition is slow and error-prone.

Route groups let you assign different root layouts per section.

This keeps code organized and easy to update.

Practice

1. What is the main purpose of using multiple root layouts in a Next.js app?

easy

A. To load all pages with the same layout

B. To change the URL structure automatically

C. To have different main designs for different parts of the app

D. To disable routing in some parts of the app

Solution

1. Step 1: Understand root layouts

   Root layouts define the main design or structure for pages in a Next.js app.

2. Step 2: Purpose of multiple root layouts

   Using multiple root layouts allows different parts of the app to have their own main design, improving organization and user experience.

3. Final Answer:

   To have different main designs for different parts of the app -> Option C

4. Quick Check:

   Multiple root layouts = different main designs [OK]

Hint: Multiple root layouts mean different main designs [OK]

Common Mistakes:

• Thinking multiple root layouts change URLs
• Assuming all pages share one layout
• Believing layouts disable routing

2. Which folder name correctly creates a route group without changing the URL in Next.js?

easy

A. dashboard/(admin)/settings

B. dashboard/admin/settings

C. dashboard/[admin]/settings

D. dashboard/{admin}/settings

Solution

1. Step 1: Identify route group syntax

   Route groups use parentheses in folder names to group routes without affecting URLs.

2. Step 2: Check options

   Only dashboard/(admin)/settings uses parentheses correctly: (admin). Other options use brackets or braces which are for dynamic routes or invalid.

3. Final Answer:

   dashboard/(admin)/settings -> Option A

4. Quick Check:

   Route groups use parentheses ( ) [OK]

Hint: Route groups use ( ) in folder names [OK]

Common Mistakes:

• Using square brackets [] for route groups
• Using curly braces {} which are invalid
• Confusing dynamic routes with route groups

3. Given this folder structure:

app/
  (marketing)/
    layout.js
    page.js
  (dashboard)/
    layout.js
    dashboard/page.js

What layout will the page at URL / use?

medium

A. Both layouts will be combined

B. The layout from (dashboard) folder

C. No layout will be applied

D. The layout from (marketing) folder

Solution

1. Step 1: Understand route groups and root layouts

   Route groups like (marketing) and (dashboard) separate parts of the app with their own layouts.

2. Step 2: Determine which route group matches URL '/'

   The root URL '/' matches the (marketing) group because it is the default or main group for the homepage.

3. Final Answer:

   The layout from (marketing) folder -> Option D

4. Quick Check:

   URL '/' uses (marketing) layout [OK]

Hint: Root URL uses main route group's layout [OK]

Common Mistakes:

• Assuming dashboard layout applies to '/'
• Thinking layouts combine automatically
• Believing no layout applies by default

4. You created a route group folder named (admin) but your app shows a 404 error when visiting /admin. What is the likely mistake?

medium

A. You forgot to restart the Next.js server

B. Route group folders do not change URLs, so /admin URL does not exist

C. You must add a dynamic route file inside (admin) folder

D. Parentheses in folder names are invalid syntax

Solution

1. Step 1: Understand route groups and URLs

   Route groups using parentheses group routes but do not add to the URL path.

2. Step 2: Check URL vs folder name

   The folder (admin) does not create /admin URL. To have /admin URL, folder must be named 'admin' without parentheses.

3. Final Answer:

   Route group folders do not change URLs, so /admin URL does not exist -> Option B

4. Quick Check:

   Route groups don't add URL segments [OK]

Hint: Route groups don't add URL parts [OK]

Common Mistakes:

• Thinking (admin) folder creates /admin URL
• Believing parentheses are invalid
• Assuming dynamic routes are needed here

5. You want to create two separate main layouts: one for public pages and one for user dashboard pages. You also want URLs like /login and /dashboard/profile. How should you organize your folders using multiple root layouts and route groups?

hard

A. Create app/(public)/layout.js and app/(dashboard)/layout.js, put pages inside each, and use route groups to keep URLs clean

B. Create app/public/layout.js and app/dashboard/layout.js folders without parentheses

C. Put all pages in app/layout.js and use conditional rendering inside layout

D. Use dynamic routes like app/[section]/layout.js to switch layouts

Solution

1. Step 1: Use route groups for separate layouts

   Route groups with parentheses let you organize folders without affecting URLs, perfect for multiple root layouts.

2. Step 2: Organize folders for public and dashboard

   Creating (public) and (dashboard) folders with their own layouts keeps code clean and URLs like /login and /dashboard/profile work as expected.

3. Final Answer:

   Create app/(public)/layout.js and app/(dashboard)/layout.js, put pages inside each, and use route groups to keep URLs clean -> Option A

4. Quick Check:

   Route groups + multiple root layouts = clean URLs and separate designs [OK]

Hint: Use ( ) folders for layouts without changing URLs [OK]

Common Mistakes:

• Not using parentheses, causing URL changes
• Putting all pages under one layout losing separation
• Using dynamic routes incorrectly for layouts