How to change a Next.js app port

Aug 21, 2020

Learn how to change the port a Next.js app runs on in development, away from the default 3000, by editing the dev script in package.json to use next dev -p.

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I’ve been asked how to change the HTTP port of an app built using Next.js, when you are running it locally. By default the port is 3000, but that’s a commonly used port and perhaps you have another service running on it.

How can you change it?

The answer is in the package.json file stored in the Next.js app main folder.

By default the file content is this:

{
  "name": "learn-starter",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start"
  },
  "dependencies": {
    "next": "9.3.5",
    "react": "16.13.1",
    "react-dom": "16.13.1"
  }
}

Note: the exact packages numbers will differ in your case, as they get updated

The thing you need to change is the scripts part.

Change:

"dev": "next dev",

"dev": "next dev -p 3001"

to start Next.js on port 3001 instead of 3000.

Now when you run npm run dev, the command used to start the development server locally, you will see it start on port 3001:

Browser showing Next.js welcome page running on localhost:3001 instead of default port 3000

Tagged: Next.js · All topics

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