Port 4200 is already in use. Use ‘-port’ to specify a different port error occures sometimes when we run our angular app using
That means there is another existing service already running on port 4200.
Port 4200 is already in use.Use ‘-port’ to specify a different port error Reasons
- An existing application(not angular) in your system using the port number 4200. This is a very rare scenario. In this case, you need to change the port number of angular application as mentioned below.
- You already ran
ng serveand to exit the application you typed Control Z (Ctrl+Z), And then you typed
ng servethen you will get
port 4200 is already in use_ error. In this case, you need to kill the previous process
To close or terminate the angular instance always use Control+C (Ctrl+c)
ng serve uses default port number 4200 to run the angular application. And our application URL will be http://localhost:4200. To avoid this error we need to change the port number to other port which is free.
According to RFC 793 port numbers is a 16-bit unassigned integer. The minimum value is 0 and the maximum value is 65535.
And, within this range, ports 0 – 1023 are reserved for specific purposes(mostly).
To change the port number for our angular application use the below command
ng serve --port 4201
Our angular application will be running on http://localhost:4201
To kill already existing angular process use the below commands
Fix Port 4200 is already in use.Use ‘-port’ to specify a different port error in Mac & Linux
To fix port 4200 is already in use error in In Mac & Linux OS (Ubuntu etc) use the following commands
sudo kill $(sudo lsof -t -i:4200) Or sudo kill `sudo lsof -t -i:4200` Or sudo lsof -t -i tcp:4200 | xargs kill -9
Fix Port 4200 is already in use.Use ‘-port’ to specify a different port error in Window
In Window operating system open command prompt. Use the following command to fix port 4200 is already in use error.
netstat -a -n -o | findStr "4200"`
Take the process id and kill the process using the following command
taskkill -f /pid 11128