Create React App with Express in Production


You’ve got a React app, and an API server written in Express or something else. Now “ how do you deploy them both to production?

There are a few ways to do this:

  • Keep them together “ Express and React files sit on the same machine, and Express does double duty: it serves the React files, and it also serves API requests.

    • e.g., a DigitalOcean VPS running Express on port 80
  • Split them apart “ Host the Express API on one machine, and the React app on another.
    • e.g., React app served by Amazon S3, API server running on a DigitalOcean VPS
  • Put the API behind a proxy “ Express and React app files sit on the same machine, but served by different servers
    • e.g., NGINX webserver proxies API requests to the API server, and
      also serves React static files

This article will cover how to keep them together. Well build the Express server to serve Reacts static files in addition to providing an API, and then deploy it to Heroku. Heroku is easy to deploy to and free to get started with.

Make a Heroku Account

If you dont have one already, go here and sign up. Its free.

Install Heroku Toolbelt

Heroku comes with a commandline command they call a toolbelt. Follow the instructions here to install it. (On a Mac with Homebrew, just brew install heroku).

The App

Well build a password generator. Every time you load the app or click Get More youll get 5 random paswords.

Finished product

Create the Express App

Make a parent directory to contain everything. Call it rando or whatever you want.

$ mkdir rando; cd rando

Initialize the project with Yarn or NPM:

$ yarn init -y
 # or npm init -y

We need 2 packages: Express itself, and a password generator. Install those now:

$ yarn add express password-generator

Create a file called index.js, which will be the Express app, and type this in:

const express = require('express');
const path = require('path');
const generatePassword = require('password-generator');

const app = express();

app.use(express.static(path.join(__dirname, 'client/build')));

app.get('/api/passwords', (req, res) => {
 const count = 5;

 const passwords = Array.from(Array(count).keys()).map(i =>
 generatePassword(12, false)


 console.log(`Sent ${count} passwords`);

app.get('*', (req, res) => {

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

console.log(`Password generator listening on ${port}`);

Were also going to need a start script in package.json, so that Heroku knows how to start the app. Open package.json and add a scripts section at the bottom. The full file should look something like this:

 "name": "rando",
 "version": "1.0.0",
 "main": "index.js",
 "license": "MIT",
 "dependencies": {
 "express": "^4.15.3",
 "password-generator": "^2.1.0"
 "scripts": {
 "start": "node index.js"

Test It

Its always good to make sure things are working as you go along. Much better than getting to the end and realizing nothing works. So, lets try it out.

Start up the Express app by running:

$ yarn start

Open up your browser and go to http://localhost:5000/api/passwords. You should see something like this:

Password generator working

Set Up Heroku

Now well deploy the app to Heroku, make sure it works, and then well add React to the mix.

Git Init

Heroku needs your project to have a Git repository, so well create one along with a .gitignore file to ignore node_modules, and then commit the code:

$ git init
$ echo node_modules > .gitignore
$ git add .
$ git commit -m "Initial commit"

Now were ready for Heroku. Run its ˜create command:

$ heroku create

And youll see something like this:

Heroku created

To make it work, we just need to push up our code by running:

$ git push heroku master

It will print out a bunch of stuff, and then the app will be live. One of the last lines will tell you the URL of the app:

My Heroku URL

Now you can go to <your url>/api/passwords and make sure it works.

Woohoo! Youve got an app live on the real internet! Except its not very nice to use, yet. Lets add a React frontend now.

Create the React App

Were going to use Create React App to generate a project. Remember that we decided the React app would live in the client folder? (we did, back when we set up Express to point to client/build for static assets).

If you dont have Create React App installed yet, do that first:

$ yarn global add create-react-app
# or npm install -g create-react-app

Generate the React app inside the Express app directory:

$ create-react-app client

Create React App will proxy API requests from the React app to the Express app if we add a proxy key in package.json like this:

"proxy": "http://localhost:5000"

This goes in client/package.json, not in the Express apps package.json, and it will be ignored by Heroku after deploying.

Open up src/App.js and replace it with this:

<code class="language-jsx">import React, { Component } from 'react';
import './App.css';

class App extends Component {
 // Initialize state
 state = { passwords: [] }

 // Fetch passwords after first mount
 componentDidMount() {

 getPasswords = () => {
 // Get the passwords and store them in state
 .then(res => res.json())
 .then(passwords => this.setState({ passwords }));

 render() {
 const { passwords } = this.state;

 return (
 <div className="App">
 {/* Render the passwords if we have them */}
 {passwords.length ? (
 <h1>5 Passwords.</h1>
 <ul className="passwords">
 Generally it's bad to use "index" as a key.
 It's ok for this example because there will always
 be the same number of passwords, and they never
 change positions in the array.
 {, index) =>
 <li key={index}>
 Get More
 ) : (
 // Render a helpful message otherwise
 <h1>No passwords :(</h1>
 Try Again?

export default App;

You can update the CSS too, if you like (in src/App.css):

<code class="language-css">.App {
 text-align: center;
 font-family: "Courier New", monospace;
 width: 100%;

h1 {
 font-weight: normal;
 font-size: 42px;

.passwords {
 list-style: none;
 padding: 0;
 font-size: 32px;
 margin-bottom: 2em;

.more {
 font-size: 32px;
 font-family: "Courier New", monospace;
 border: 2px solid #000;
 background-color: #fff;
 padding: 10px 25px;
.more:hover {
 background-color: #FDD836;
.more:active {
 background-color: #FFEFA9;

Now start up the React app by running yarn start inside the client folder.

Make sure the Express app is running too: run yarn start from its folder as well.

Go to http://localhost:3000 and the app should be working! Now we can deploy the whole thing to Heroku.

Deploying to Heroku

When you deploy the app with the git push heroku master command, git copies all the checked-in files up to Heroku. There are two complications now:

  • We need to check in the new client code
  • Express depends on the built client code in client/build, which we dont have yet, and which wed rather not check in to git.

What well do is tell Heroku to build the React app after we push up the code, and we can do that by adding a heroku-postbuild script in the top-level (Express apps) package.json:

"scripts": {
 "start": "node index.js",
 "heroku-postbuild": "cd client && yarn --production=false && yarn run build"

This tells Heroku hey, after youre done doing what you do, go into the client folder and build my React app. The yarn run build script will kick off Create React Apps production build, which will put its output files in the client/build folder so Express can find them.

The --production=false flag might look odd. Its there because by default, yarn will not install devDependencies in production, and we need those (react-scripts in particular) to build the React app.

Once you make that change, add everything to git (run this from the top-level rando directory, not inside client):

$ git add .
$ git commit -m "Ready for awesome"

And deploy it:

$ git push heroku master

It again prints out your apps hostname. Mine is Go there and try it out!

Congrats, youve got a React + Express app in production 😉

Create React App with Express in Production was originally published by Dave Ceddia at Dave Ceddia on June 07, 2017.