How to fix Error: listen EADDRINUSE while using NodeJS?

What really helped for me was:

killall -9 node

But this will kill a system process.

With

ps ax

you can check if it worked.

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EADDRINUSE means that the port number which listen() tries to bind the server to is already in use.

So, in your case, there must be running a server on port 80 already.

If you have another webserver running on this port you have to put node.js behind that server and proxy it through it.

You should check for the listening event like this, to see if the server is really listening:

var http=require('http');

var server=http.createServer(function(req,res){
    res.end('test');
});

server.on('listening',function(){
    console.log('ok, server is running');
});

server.listen(80);

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The aforementioned killall -9 node, suggested by Patrick works as expected and solves the problem but you may want to read the edit part of this very answer about why kill -9 may not be the best way to do it.

On top of that you might want to target a single process rather than blindly killing all active processes.

In that case, first get the process ID (PID) of the process running on that port (say 8888):

lsof -i tcp:8888

This will return something like:

COMMAND   PID    USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
node     57385   You   11u  IPv6 0xac745b2749fd2be3      0t0  TCP *:ddi-tcp-1 (LISTEN)

Then just do (ps - actually do not. Please keep reading below):

kill -9 57385

You can read a bit more about this here.

EDIT: I was reading on a fairly related topic today and stumbled upon this interesting thread on why should i not kill -9 a process.

Generally, you should use kill -15 before kill -9 to give the target process a chance to clean up after itself. (Processes can't catch or ignore SIGKILL, but they can and often do catch SIGTERM.) If you don't give the process a chance to finish what it's doing and clean up, it may leave corrupted files (or other state) around that it won't be able to understand once restarted.

So, as stated you should better kill the above process with:

kill -15 57385

EDIT 2: As noted in a comment around here many times this error is a consequence of not exiting a process gracefully. That means, a lot of people exit a node command (or any other) using CTRL+Z. The correct way of stopping a running process is issuing the CTRL+C command which performs a clean exit.

Exiting a process the right way will free up that port while shutting down. This will allow you to restart the process without going through the trouble of killing it yourself before being able to re-run it again.

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Just a head's up, Skype will sometimes listen on port 80 and therefore cause this error if you try to listen on port 80 from Node.js or any other app.

You can turn off that behaviour in Skype by accessing the options and clicking Advanced -> Connection -> Use port 80 (Untick this)

https://i.stack.imgur.com/OXiXH.png

P.S. After making that change, don't forget to restart Skype!

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You should try killing the process that is listening on port 80.

Killall will kill all the node apps running. You might not want to do that. With this command you can kill only the one app that is listening on a known port.

If using unix try this command:

sudo fuser -k 80/tcp    

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Error reason: You are trying to use the busy port number

Two possible solutions for Windows/Mac

Free currently used port number Select another port number for your current program

1. Free Port Number

Windows

1. netstat -ano | findstr :4200
2. taskkill /PID 5824 /F

https://i.stack.imgur.com/Sgx6K.png

Mac

You can try netstat

netstat -vanp tcp | grep 3000

For OSX El Capitan and newer (or if your netstat doesn't support -p), use lsof

sudo lsof -i tcp:3000

if this does not resolve your problem, Mac users can refer to complete discussion about this issue Find (and kill) process locking port 3000 on Mac

2. Change Port Number?

Windows

set PORT=5000

Mac

export PORT=5000

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Under a controller env, you could use:

pkill node before running your script should do the job.

Bear in mind this command will kill all the node processes, which might be right if you have i.e a container running only one instance, our you have such env where you can guarantee that.

In any other scenario, I recommend using a command to kill a certain process id or name you found by looking for it programmatically. like if your process is called, node-server-1 you could do pkill node-server-1.

This resource might be useful to understand: https://www.thegeekstuff.com/2009/12/4-ways-to-kill-a-process-kill-killall-pkill-xkill/

---

lsof -i:3000;
kill -9 $(lsof -t -i:3000);
// 3000 is a your port
// This "lsof -i:3000;" command will show PID 
kill PID 
ex: kill 129393

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Another thing that can give this error, is two HTTP servers in the same node code. I was updating some Express 2 to Express 3 code, and had this...

http.createServer(app).listen(app.get('port'), function(){            
  console.log('Express server listening on port ' + app.get('port')); 
});        

// tons of shit.

http.createServer(app).listen(app.get('port'), function(){            
  console.log('Express server listening on port ' + app.get('port')); 
});                                                                   

And, it triggered this error.

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Your application is already running on that port 8080 . Use this code to kill the port and run your code again

sudo lsof -t -i tcp:8080 | xargs kill -9

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This works for me (I'm using mac). Run this command

lsof -PiTCP -sTCP:LISTEN

This's going to display a list of ports that your syetem is using. Find the PID that your node is running

COMMAND     PID          USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
node      17269 hientrq   16u  IPv6 0xc42959c6fa30c3b9      0t0  TCP *:51524 (LISTEN)
node      17269 hientrq   19u  IPv4 0xc42959c71ae86fc1      0t0  TCP localhost:1337 (LISTEN)

and run kill -9 [YOUR_PID]

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EADDRINUSE means that the port(which we try to listen in node application) is already being used. In order to overcome, we need to identify which process is running with that port.

For example if we are trying to listen our node application in 3000 port. We need to check whether that port is already is being used by any other process.

step1:

$sudo netstat -plunt |grep :3000

That the above command gives below result.

tcp6       0      0 :::3000                 :::*                    LISTEN      25315/node

step2:

Now you got process ID(25315), Kill that process.

kill -9 25315

step3:

npm run start

Note: This solution for linux users.

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sudo kill $(sudo lsof -t -i:80)

for force kill

sudo kill -9 $(sudo lsof -t -i:80)

use above cmd to kill particular port and then run your server

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Try both commands and it will stop all node process.

killall 9 node
pkill node
npm start 

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There is a way to terminate the process using Task Manager:

Note that this solution is for Windows only

Go to the Task Manager (or using the shortcut Ctrl + Shift + Esc) On "Background Processes", find "Node.js" processes and terminate them (Right-click them and choose "End Task")

https://i.stack.imgur.com/aIYey.png

Now you should be able to start again

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In below command replace your portNumber

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

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This error comes when you have any process running on a port on which you want to run your application.

how to get which process running on that port=> command: sudo netstat -ap | grep :3000

output : you will get the process information which is using that port

tcp 0 0 IPaddress:3000 : LISTEN 26869/node

Now you can kill that process sudo kill -9 26869

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EADDRINUSE means port of your nodejs app is already in use.

Now you have kill the process/app running on that port.

Find the process id of app by:

lsof -i tcp:3000

Now u will get process id from this.

Run this:

kill -9 processId

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I got:

Error: listen EADDRINUSE: address already in use :::8000

I was trying to look for the process listening to port 8000
and had no luck - there were none (sudo netstat -nlp | grep 8000 ).

It turned out I had app.listen(8000) written twice in my script.

My assumption is that the interference was happening only in a short time when trying to run the script, so looking for processes listening to the port before and after error didn't show any.

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I have seen this error before (in node) with http.client, and as I recall, the problem had to do with not initializing the httpClient or setting bad options in the httpClient creation and/or in the url request.

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Error: listen EADDRINUSE means the port which you want to assign/bind to your application server is already in use. You can either assign another port to your application.

Or if you want to assign the same port to the app. Then kill the application that is running at your desired port.

For a node application what you can try is, find the process id for the node app by :

ps -aux | grep node

After getting the process id, do

kill process_id

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In my case Apache HTTP Server was run on port 80 I solved it by issue the command as root

sudo killall httpd

Update

If Jenkin is installed and running on your Mac;

You can check it with sudo lsof -i tcp:8080 If Yes, and You want to stop Jenkins only once, run: sudo launchctl unload /Library/LaunchDaemons/org.jenkins-ci.plist

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I have the same problem too,and I simply close the terminal and open a new terminal and run

node server.js

again. that works for me, some time just need to wait for a few second till it work again.

But this works only on a developer machine instead of a server console..

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On Debian i found out to run on port 80 you need to issue the command as root i.e

sudo node app.js

I hope it helps

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Two servers can not listen on same port, so check out if other server listening on same port, also check out for browser sync if its running on same port

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For other people on windows 10 with node as localhost and running on a port like 3500, not 80 ...

What does not work:

killall    ?  command not found
ps -aux | grep 'node'     ?     ps:  user x unknown 

What shows information but still not does work:

 ps -aef | grep 'node'
 ps ax
 kill -9 61864

What does work:

Git Bash or Powershell on Windows

  net -a -o | grep 3500   (whatever port you are looking for) 

Notice the PID ( far right )
I could not get killall to work... so

Open your task manager On processes tab , right click on Name or any column and select to include PID Sort by PID, then right click on right PID and click end task.

Now after that not so fun exercise on windows, I realized I can use task manager and find the Node engine and just end it.

FYI , I was using Visual Studio Code to run Node on port 3500, and I use Git Bash shell inside VS code. I had exited gracefully with Ctrl + C , but sometimes this does not kill it. I don't want to change my port or reboot so this worked. Hopefully it helps others. Otherwise it is documentation for myself.

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For windows users execute the following command in PowerShell window to kill all the node processes.

Stop-Process -processname node

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The error EADDRINUSE (Address already in use) reports that there is already another process on the local system occupying that address / port.

There is a npm package called find-process which helps finding (and closing) the occupying process.

Here is a little demo code:

const find = require('find-process')

const PORT = 80

find('port', PORT)
.then((list) => {
  console.log(`Port "${PORT}" is blocked. Killing blocking applications...`)
  const processIds = list.map((item) => item.pid)
  processIds.forEach((pid) => process.kill(pid, 10))
})

I prepared a small sample which can reproduce the EADDRINUSE error. If you launch the following program in two separate terminals, you will see that the first terminal will start a server (on port "3000") and the second terminal will close the already running server (because it blocks the execution of the second terminal, EADDRINUSE):

Minimal Working Example:

const find = require('find-process')
const http = require('http')

const PORT = 3000

// Handling exceptions
process.on('uncaughtException', (error) => {
  if (error.code === 'EADDRINUSE') {
    find('port', PORT)
      .then((list) => {
        const blockingApplication = list[0]
        if (blockingApplication) {
          console.log(`Port "${PORT}" is blocked by "${blockingApplication.name}".`)
          console.log('Shutting down blocking application...')
          process.kill(blockingApplication.pid)
          // TODO: Restart server
        }
      })
  }
})

// Starting server
const server = http.createServer((request, response) => {
  response.writeHead(200, {'Content-Type': 'text/plain'})
  response.write('Hello World!')
  response.end()
})

server.listen(PORT, () => console.log(`Server running on port "${PORT}"...`))

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I had the same issue recently.

It means that the port is already being used by another application (express or other software)

In my case, I had accidentally run express on 2 terminals, so exiting the terminal using 'Ctrl + C' fixed things for me. (Run server from only one terminal)

Hope it helps others.

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Seems there is another Node ng serve process running. Check it by typing this in your console (Linux/Mac):

ps aux|grep node

and quit it with:

kill -9 <NodeProcessId>

OR alternativley use

ng serve --port <AnotherFreePortNumber>

to serve your project on a free port of you choice.

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