Nodemon: Error: listen EADDRINUSE: address already in use :::5000

Question

I'm creating a project and using nodejs, express for the backend. Everything works fine but as I make any change in the file, nodemon is unable to restart the server due to following error:

Error: listen EADDRINUSE: address already in use :::5000

index.js:

const express = require("express");
const morgan = require("morgan");
const mongoose = require("mongoose");
const cookieParser = require("cookie-parser");
const session = require("express-session");
const FileStore = require("session-file-store")(session);
const dotenv = require("dotenv");
var passport = require("passport");

dotenv.config();

const PORT = process.env.PORT || 5000;

const app = express();

.....

app.listen(PORT, () => console.log(`Server listening on port ${PORT}!`));

package.json

{
  "name": "chat-app-backend",
  "version": "0.0.0",
  "private": true,
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon --ignore 'sessions/' index.js"
  },
  "dependencies": {
    "bcryptjs": "^2.4.3",
    "cookie-parser": "^1.4.5",
    "cors": "^2.8.5",
    "debug": "~2.6.9",
    "dotenv": "^8.2.0",
    "express": "~4.16.0",
    "express-session": "^1.17.0",
    "http-errors": "~1.6.2",
    "jade": "~1.11.0",
    "jsonwebtoken": "^8.5.1",
    "mongoose": "^5.9.4",
    "morgan": "~1.9.0",
    "passport": "^0.4.1",
    "passport-jwt": "^4.0.0",
    "passport-local": "^1.0.0",
    "passport-local-mongoose": "^6.0.1",
    "session-file-store": "^1.4.0",
    "uuid": "^7.0.2"
  },
  "devDependencies": {
    "nodemon": "^2.0.2"
  }
}

I've to explicitly kill the server from the terminal every time, which is not the optimal solution. I tried several things, but none are working. Even found some issue in nodemon GitHub issue page, but there also I couldn't find anything.

I'm also adding the output of lsof -i:5000, even if server I'm closing the server - *node 31625 rishav 20u IPv6 5300049 0t0 TCP :5000 (LISTEN)

Answer 1

--delay helped me to fix both of issues

• on auto-restart

• stopping with ctrl-c

  nodemon --delay 500ms app.js
  

And I also added:

process.once('SIGUSR2', function () {
  process.kill(process.pid, 'SIGUSR2');
});

process.on('SIGINT', function () {
  // this is only called on ctrl+c, not restart
  process.kill(process.pid, 'SIGINT');
});

Answer 2

I had the same situation. If you are using Visual Studio Code, check your terminals. You might have other instances of the terminal that is already running your node server.

Answer 3

I think that error happens to me when I shut down the server's terminal without turning off nodemon beforehand.

Then, usually the next day, nodemon starts acting weird.

How I solved it: What I noticed is that when running ps -fp $(grep -u my_username), I got several instances of nodemon up and running. So I did pkill -f nodemon, which killed all nodemon instances, and then relaunched nodemon and all was good again in the wonderful realm of my Linux server.

Answer 4

You can try running your server on some other port like 3000.

If you still want to use the same port, then you can use the following command to get the list of running process on that particular port:

lsof -i tcp:3000 

Use following command in the terminal to kill that running port:

sudo kill -9 $(lsof -i tcp:3000 -t)

Answer 5

None of all the aforementioned solutions worked for me. I simply had to do this every time:

npx kill-port 5000

Answer 6

I had the same problem, every time when I saved files the error occurred.

** Updated on 3/18/2021 **

• The fastest and direct way for me to solve this problem is by restarting the computer.
• I am sure nodemon is still running somewhere even I re-open VS editor, which makes that address conflict.
• This problem happens few times in my case.
• I am still trying to figure out the root of the problem. This is not a perfect solution.

** End **

I need to exit the nodemon mode, find out the PID, and kill it. This is not a good solution because it is troublesome and it blocks me from getting the debugging logs in the terminal.

But I found another way to fix the problem, just change the file name from server.js to another name (for example, I tried server1.js), also change the script in the package.json file.("server": npx nodemon server1.js), finally run npm run server.

Before:

Here is what I did:

1. Change the file name from server.js to server1.js.
2. Change the script in the package.json file, from "server": "npx nodemon server.js" to "server": "npx nodemon server1.js".
3. $ npm run server.

After:

I know this is a weird solution, maybe something is wrong with my computer or the nodemon package, but eventually, it does work for me, the file name does matter.

Here is an interesting observation I found on November 1, 2020:

1. If you have both files, server.js and server1.js, and they have the same port number (8000), when npm run server, the error occurs.
2. It seems that nodemon will run server.js automatically by default. Even though I only have "server": "npx nodemon server1.js" in package.json, when my terminal executes npm run server command, nodemon runs server.js and server1.js at the same time.
3. Since server.js and server1.js have the same port number, that makes the error occurred.
4. In a similar way, if we only have server.js, nodemon runs server.js automatically, then runs server.js according to package.json script, the error will occur.

Hope this will help. Please feel free to let me know if this works for your applications.