Next.js MCP Server Setup: Complete Guide for Developers

If you’re working with Next.js 16+, then you know how essential developer tools like MCP Server are to improve productivity, debug issues faster, and optimize your app.

Today, I want to introduce you to the powerful Next.js MCP. It provides real-time, granular insights into your Next.js development server, directly within the coding agent!

In this blog post, I’ll walk you through everything you need to get started with Next.js MCP and how you can use it to supercharge your headless development workflow.

What is Next.js MCP?

Next.js MCP is a plugin that allows the Coding agent to connect directly with your Next.js 16+ development server. Once connected, you can access all sorts of real-time data, including:

• File structure exploration
• Route inspection
• API route debugging
• Component tree exploration
• Build output and bundle size analysis
• Error and log tracking

With Next.js MCP, you gain powerful insights into your project that make it easier to maintain and optimize your Next.js app, especially for complex applications like eCommerce systems.

Requirements for Using Next.js MCP Server

Before we dive into the setup, let’s first review the basic requirements for using Next.js MCP Server:

1. Node.js 18+
2. Next.js 16+ (App Router recommended)
3. npx available in your PATH
4. A local development server running.

How to Set Up Next.js MCP

Getting started with Next.js MCP is simple. Just follow these three steps, and you’ll be up and running in no time.

Step 1: Create .mcp.json File

Create a file called .mcp.json in your project root directory, and add the following configuration:

{
  "mcpServers": {
    "next-devtools": {
      "command": "npx",
      "args": ["-y", "next-devtools-mcp@latest"]
    }
  }
}

This configuration registers the MCP server, allowing Coding agent to connect and interact with your local Next.js dev server.

Step 2: Start Your Development Server

Start your development server with:

npm run dev

If you want to run the server on a custom port, use:

next dev -p 3001

Once the server is running, Next.js MCP will automatically detect your Next.js instance, including routes, logs, errors, and build output.

Step 3: Connect Coding agent

Once everything is set up, Coding agent will automatically connect to the MCP server. You’ll see:

✔ Connected to next-devtools-mcp
✔ Ready to inspect your project

Congratulations! You’re all set to start inspecting and optimizing your Next.js app.

What Can You Do with Next.js MCP?

Here’s a quick overview of what you can achieve with Next.js MCP.

File System Tools

• View your entire Next.js project structure and navigate files effortlessly.
• Analyze component decomposition to improve code structure.
• Identify dead code and areas for optimization.
• Suggest better caching strategies to improve performance.

Route Inspection

• List all routes, whether using App Router or Pages Router.
• Show route definitions and which server components are used.
• Identify slow components that may be causing render lag.

Build and Performance Tools

• Analyze your server and client bundle sizes to spot large, unnecessary dependencies.
• Visualize the React Server Components graph to optimize your rendering logic.
• Get performance warnings for slow or blocking dependencies.
• Recommend caching optimizations, like revalidatePath or unstable_cache.

Debugging Tools

• Inspect server logs for debugging runtime issues.
• Capture errors and stack traces to pinpoint issues quickly.
• Inspect API route input and output, and find invalid cache usage or misconfigurations.

Developer Productivity Tools

• Generate component templates to speed up development.
• Suggest folder structures to keep your project organized.
• Provide migration recommendations when upgrading Next.js versions.
• Suggest code modifications (e.g., migrations, optimizations).

A Sample Development Workflow with Next.js MCP

Here’s how you can incorporate Next.js DevTools MCP into your daily development routine:

1. Start your Next.js server: npm run dev
2. Ask Coding agent to perform tasks such as:
   • “Inspect all routes”
   • “Analyze why this page loads slow”
   • “Show bundle size for the PDP”
   • “Optimize server action caching”
   • “Show edge runtime errors”
3. Apply fixes suggested by Coding agent:
   • Move heavy logic to server components.
   • Use Segment-level caching for optimization.
   • Introduce Partial Prerendering (PPR).
   • Add revalidateTag() for cache invalidation.
4. Get automatic debug logs:
   Every time you save your code, the build logs, warnings, and errors are sent directly to Coding agent, making it easier to catch and fix issues in real time.
5. Repeat:
   Continue improving your code with Coding agent suggestions for clean folder structures, optimized caching, and fast routing.

Key Tools Available in Next.js MCP

Here are some key tools that a coding agent can access via the MCP:

Available Tools	Description
next.routes.list	List all App Router routes
next.config.get	Read next.config.js
next.fs.read	Read any file in your project
next.fs.list	List project directories
next.build.info	Show build outputs
next.bundle.analyze	Analyze bundle size
next.server.logs	View server logs
next.errors.list	View recent errors
next.route.inspect	Inspect specific routes
next.components.tree	Visualize component hierarchy
next.api.inspect	Inspect API route responses

Next.js MCP server Real-World Examples

Let’s look at a few real-world examples of how you can use Next DevTools MCP in your development workflow.

Example 1: List All Routes

Query: “List all App Router routes”

Output:

/ (RSC)
 /products/[slug]
 /api/products
 /cart
 /profile/settings

Example 2: Inspect a Route

Query: “Inspect the route /products/[slug]”

Output:

Server Component: PDPPage
Client Components: Gallery, AddToCart
Database Query: getProductBySlug()
Cache: revalidate = 3600
Bundle Size: 89kb
Perf Warning: Gallery contains heavy JS (move to RSC)

Example 3: Bundle Size Analysis

Query: “Analyze the server bundle size”

Output:

Largest modules:
 lodash-es (58kb)
 swiper (44kb)
 moment (34kb) — DEPRECATED

Example 4: Errors

Query: “Show all current Next.js errors”

Output:

1. Warning: fetch() used in Client Component
2. Error: api/cart missing return response
3. Warning: dynamic = 'force-dynamic' used unnecessarily

How It Works

1. Start your Next.js dev server: This exposes internal debugging endpoints.
2. MCP starts automatically via npx and attaches to:
   • File watcher
   • Route manifest
   • Turbopack hooks
   • React Server Components output
3. Coding agent detects MCP server and communicates with it via a WebSocket.
4. Requests: Coding agent makes requests to MCP tools, which fetch real-time data from your Next.js instance.
5. Optimization: Coding agent processes the data and offers real-time suggestions for code improvements.

Troubleshooting

Here are a few common issues and their solutions:

1. MCP not connecting?

• Restart your Next.js server and refresh Coding agent.

2. Project not detected?

• Ensure you’re running the command inside the project root.

3. Port in use?

• Change the port with: next dev -p 3005

4. Reading files not working?

• Ensure .mcp.json is located at the project root.

5. Logs not showing?

• Enable verbose logging with: NEXT_PRIVATE_DEBUG=1 npm run dev

Conlusion

Next.js DevTools MCP is a game-changer for Next.js developers who want to optimize their workflows, debug issues quickly, and improve performance across large-scale applications.

Integrating with the Coding agent gives you real-time data, insights, and optimizations. Whether building a complex web app, this tool helps you build faster, smarter, and more efficiently.

We provide an open source headless eCommerce platform that’s free to use and ultra-fast, allowing you to set up your online store in just a few clicks.

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