Create-react-app: Option to specify port when running the server?

[ghost]

My project is based on create-react-app. npm start by default will run the application on port 3000 and there is no option of specifying a port in the package.json.

How can I specify a port of my choice in this case? I want to run two of this project simultaneously (for testing), one in port 3005 and other is 3006

SO Question

[riceyeh]

You can specify your port with process.env.PORT. It can be done by changing the script for start in package.json as shown below:

"start": "PORT=3006 react-scripts start"

[ghost]

You mean my package.json will be

{
  "start": "PORT=3006 react-scripts start",
  "name": "igene-web",
  "version": "0.1.0"......... }

then npm start?

didn't work for me (windows and ubuntu)

[dvkndn]

@fireflieslive no it is not. You should change the start command inside scripts section in your package.json

[ghost]

haha, where am i looking. thanks!

[dvkndn]

You're welcome. If your issue is solved you can close the issue :D

[ghost]

works with ubuntu, not with windows:

'PORT' is not recognized as an internal or external command,
operable program or batch file.

[dvkndn]

The above command is Unix (Ubuntu, Mac, etc…). In windows enviroment, you need a different syntax. Google something like "set env in windows command line"

[Delapouite]

For windows you can use cross-env https://www.npmjs.com/package/cross-env

[gaearon]

You can also create an .env file with

PORT=3006

and save it in your project directory.

[rugglcon]

This worked for me on elementaryOS, thanks!

[philipjmurphy]

On Windows with yarn this worked for me:

"scripts": {
    "start": "set PORT=3006 && react-scripts start",
    ....

[ulrikwalter]

Or use npm cross-env (without &&!)

"scripts": {
    "start": "cross-env PORT=3006 react-scripts start",
}

[webmobiles]

how to do it with the build folder ?

[Timer]

Deployment is a bit different, you can read our documentation on that @webmobiles.
Open an issue if you run into any trouble / find something wrong!

[aleczratiu]

"start": "PORT=3006 react-scripts start"
in package.json change it.