Changing Default React JS Port Number

When developing a React JS application, the default port number that the application runs on is 3000. This is the default port that the React development server uses to serve your application.

However, there may be situations where you need to change this default port number. For example, if you have multiple React applications running on your machine, you may encounter conflicts with the default port number. Or, if the default port is already being used by another application on your machine, you will need to change the port number for your React application.

How to Change the Default Port Number

To change the default port number for your React application, you can use the PORT environment variable. This allows you to specify a different port number for your application to run on.

Here’s how you can do this:

1. Create a new file called .env in the root directory of your React project.
2. Inside this file, add the following line: PORT=3001 (or whatever port number you want to use).
3. Save the file and restart your React development server.

After doing this, your React application will now run on the specified port number instead of the default 3000.

Considerations

It’s important to note that when changing the default port number, you should also update any references to the old port number in your code. This includes any API calls or other external resources that may be using the old port number.

Additionally, if you are using a proxy server to make API calls in your React application, you will need to update the proxy configuration to use the new port number.

Conclusion

Changing the default port number for your React JS application is a simple process that can help you avoid conflicts and allow you to run multiple applications on the same machine. By using the PORT environment variable, you can easily specify a different port number for your application to run on.