how to run angular 4 app and nodejs api on same port 4200 for both production and development?

All we need is an easy explanation of the problem, so here it is.

I have created angular 4 app and I can run it using ng serve --open and it runs on localhost:4200 ,
what I want is I have also created api using nodejs in same angular project now I want to run that API at localhost:4200/api so I have tried something like this

my angular 4 and nodejs srtucture look like this


in app.js I used

app.use(express.static(path.join(__dirname, 'dist')));
app.use('/app/api', apiRoutes);
const port = process.env.PORT || '3000';
server.listen(port, () => console.log(`API running on localhost:${port}`));

Once I run using nodemon app.js and go at localhost:3000 it run my angular app and it’s fine and than I go at localhost:3000/app/api it’s also work fine and good ,

But when I change in angular app it’s not auto refresh my app because it’s running node app currently for refresh it I need to run ng build and than it will effect my new changes on angular app

So, What I want is to run ng serve --open it will run angular app but not node js api so want to run both and once i change in any from angular app or node js app it must be auto refresh.

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

You can’t have two different applications running on the same port. Angular-cli uses a nodejs server (technically it’s webpack-dev-server) behind the scenes when you run ng serve, which means that port is already in use.

There are two possible solutions.

  1. Use your node application to serve the static frontend files. Then you can’t really use ng serve (this is probably what you’d do when running live).

  2. Use nodejs with a different port, and use Angular’s proxy config, to have Angular think the api port is actually 4200 (this is probably best during development).

This is primarily a concern during development I reckon, since you most likely wont (and shouldn’t) be using ng serve live, so option 2 would be my best recommendation.

To configure a proxy, you create a file in your angular application root directory called proxy.config.json with the following content:

  "/api/*": {
    "target": "http://localhost:3000",
    "secure": false,
    "changeOrigin": true

Then when you run ng serve, you run it with ng serve --proxy-config proxy.config.json instead.

Here’s a link to the documentation

Here’s an alternative when building for production (solution 1 above):

To build in production you use ng build --prod to create a production ready Angular build and then (assuming you use Express on your node server), use something like app.use(express.static('dist/')) as explained in the Express documentation. I’m not using node myself (I’m using .NET Core) so I’m afraid I can’t provide much more in terms of details.

Method 2

There is one awesome blog on medium by Daniel Kagan which explain all, here the link.
Hot deploy its explain about client hot deployment i added some more code to make client and server hot deployment.

This answer is purely for development hot reload

Step one.

Install concurrently and nodemon

npm i concurrently

npm i nodemon

You can install globally as well with -g flag

Step Two.

Open your servers package.json file,
and add following four line to it. Note i have my angular code inside client folder so i did cd client

"buildclient": "cd client && ng build",
"runclient": "cd client && npm start",
"devstart": "nodemon --inspect ./bin/www",
"dev": "npm run buildclient & concurrently --kill-others \"npm run runclient\" \"npm run devstart\""

If you don’t want inspect node app then remove --inspect flag.

Step Three.

Go to your angular folder and create file proxy.conf.json add following line to file.

   "/api/*": {
   "target": "http://localhost:3000",
   "secure": false,
   "changeOrigin": true

Step Four.

Add following command inside angular’s package.json file

"start": "ng serve --proxy-config proxy.conf.json"

Step Five.

Make angular build output directory inside public folder of server. To do this go to angular.json change build outputPath to ../public following is JSON snippet.

"options": {
        "outputPath": "../public",
        "index": "src/index.html",
        "main": "src/main.ts",
        "polyfills": "src/polyfills.ts",
        "tsConfig": "src/",
        "assets": [
        "styles": [
        "scripts": []

Step Six.

Make sure your node express server app.js file read static files from public folder.

app.use(express.static(path.join(__dirname, 'public')));

Step Seven.

npm run dev

Done goto http://localhost:4200 you can see you app there 🙂 all call to /api will get to node express server.

Any changes to server or client will be hot deployed automatically.

NOTE I used Express application generator to create my server and Angular CLI to create angular application. If you did it some other way then some files might not be present

Method 3

1.first build you angular 6 app
run ng build –watch

2.from nodejs app
write this middle ware
app.use(express.static(path.join(__dirname, './client/dist/client')));
as the folder pointing to client/dist/client is build folder of angular 6 app.

then run nodemon –inspect app.js

make sure to have a hirearchy of folders like this


listen to the port you want to run from app.js
and run localhost:portno

hope this helps

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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