“Port 4200 is already in use” when running the ng serve command

Question

I am learning angular 2 and for the first time I am using the angular CLI project to create a sandbox project.

I was able to run the command \"ng serve\" and it wor

Answer 1

ng serve --port 4201 --live-reload-port 4200

and access using localhost:4201

This should work as a temporary solution.

or

try listing port usage using
lsof -i:4200
and kill it manually using
sudo kill -9 <Process PID using port 4200>

Answer 2

netstat -anp | grep ":4200"

This will tell you who's got the port.

Answer 3

Open your cmd.exe as administrator,

then Find the PID of port 4200

netstat -ano | findstr :4200

Here i have 3 PID :

• Red one is from "ng-serve" (127.0.0.1:4200) that LISTENING
• Green one is from "your browser"

kill only port 4200 (kill the red PID):

taskkill /PID 15940 /F

note : kill the green one will only lead your browser closed by force.

now you can do "ng-serve" to start your angular app at the same port 4200

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Additional Stuff :

One liner : After looking a way to optimize this, Here is the One-liner command of this answer : (special thanks to : Josep Alsina for this tips)

for /f "tokens=5" %a in ('netstat -ano ^| find "4200" ^| find "LISTENING"') do taskkill /f /pid %a

Answer 4

On Mac OS X you need the following command:

sudo lsof -t -i tcp:4200 | xargs kill -9

Remember you need to kill Angular's web server with Command+C.

Answer 5

I was facing the same issue every time I have to kill the port.

I tried ./node_modules/.bin/ng serve --proxy-config proxy.conf.json --host 0.0.0.0 Instead of npm start and its works

Answer 6

Kill process and close the terminal which you used for running the app on that port.