Next.js Project Structure
Purpose
This skill defines the folder and file conventions for Next.js App Router applications. Use this to ensure file placement dictates the correct routing behavior and architectural consistency.
Usage
When creating new features or refactoring, you must first identify the project's Organization Strategy (see below) to determine where files belong.
1. Top-Level Organization Strategies
Identify which strategy the project is using and strictly adhere to it. Do not mix strategies.
| Strategy | Description | Indicator |
|---|---|---|
Store in src | Application code lives in src/app. Config files live in root. | src/app/page.tsx exists |
Root app | Application code lives in app. Config files live in root. | app/page.tsx exists |
| Split by Feature | Global code in app; feature code colocated in route segments. | app/dashboard/_components/ exists |
| External Projects | Project files live in components/ or lib/ at root, outside app. | components/ exists at root |
2. File Conventions (Quick Ref)
Next.js uses file-system based routing. The filename determines the behavior.
- Routes: Must be named
page.tsxorroute.ts. - UI Wrappers:
layout.tsx(persistent),template.tsx(re-mounted). - Data UI:
loading.tsx(Suspense),error.tsx(Error Boundary).
For the complete table of supported file names and their hierarchy, read: references/file-conventions.md
3. Routing & Groups
Do not rely on folder names alone for URL structure.
- URL Segments:
app/blog/page.tsx->/blog - Route Groups:
app/(marketing)/page.tsx->/(Folder name omitted from URL) - Private Folders:
app/_utils/-> Not routable.
For advanced patterns (Dynamic[id], Parallel@slot, Intercepting(.)), read: references/routing-patterns.md
Validation Checklist
Before finalizing a file creation:
- Does the file name match a reserved Next.js convention (e.g.,
page.tsx)? - Is the file inside the correct Route Group (if applicable)?
- Are colocated components properly marked private (in
_folders) if they shouldn't be routable?