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How to write production ready Node.js Rest API — Javascript version

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This article list out all the necessary ingredients for the production ready Node.js rest api with plain vanilla javascript. I want to categorize this into two phases

  1. Development Phase
  2. Production Phase

Let’s not complicate things and create simple user api where you get list of users with Get request and save user with post request. since we are focussing on the Node.js rest api, lets go with the simple API. let’s download all the tools required for the project.

Tools Required:

For complete project

git clone

follow the below article for step by step process

Development Phase

  • Initial setup
  • nodemon
  • Logging
  • How to handle undefined routes
  • How to define context path
  • Linting your project
  • Testing your project

Any node.js project starts with package.json lets create a folder called user_api and cd into it and do npm init. it will ask you all the details like package name, version, author etc. You can leave them blank or give some values will create a package.json in your folder.

mkdir user_api
cd user_api
npm init

if you notice the package.json, index.js is the main file which is the starting file for the project. lets create index.js file at root level and install express.js framework. Express is a web application framework for node.js which we can use for creating http server and configure routes for our project.

touch index.js
npm install express --save

whenever you install package and it will be added to dependencies section as you can see below. you don’t have to add it manually when you do it with “ — save” flag, npm will take care of adding that into dependencies section.


let’s import express into index.js and create Http server which listens on port 3070 and create a default route with “/”.


var express = require("express"),
app = express(),
port = 3070;
app.get("/", function(req, res) {
res.send("App works!!");
app.listen(port, function(err) {
console.log("running server on from port:::::::" + port);

run the below command and open the browser and hit http://localhost:3070 and default route works!!.

node index.js
Default route working

Lets add scripts to package.json. scripts are the great place to add all your commands so that you can run with npm command. Add the below line to the scripts section in package.json. you can run with this command npm start

"scripts": {   
"start": "node index.js",
"test": "echo "Error: no test specified" && exit 1"

Lets add couple of routes and test it in the browser. add the body-parser dependency express will use this middleware to access request data from the post request. Look at the complete index.js file and package.json file.

npm install body-parser --save
//in the index.js file


At this moment, we have full rest api with 4 routes including default. one problem that we have right now is manual restart of the server whenever we edit any file. lets add nodemon. it’s a tool which automatically detects file changes in your directory and restart the server without any manual intervention.

This is a dev dependency means only necessary for development, so the flag — save-dev. add the another line to the scripts section so that we can run with npm.

npm install nodemon --save-dev
// dev dependencies will be added
"devDependencies": {
"nodemon": "^1.18.10"
// scripts section in package.json
"scripts": {
"start": "node index.js",
"start:dev": "nodemon index.js",
"test": "echo "Error: no test specified" && exit 1"

run the below npm command and edit the file you can see changes instantly without restart of the server. it boosts your productivity.

npm run start:dev


Let’s setup logging for our project. create a new folder called logger with a file called logger.js. we can use any package like winston, log4js, but we are not using those for simplicity purpose. This is how you create a separate file and import it in another file in nodejs.

Now you can see the logging is done by the logger that we created once you replace all console.log statements. in this way you can control all your app logging from one file. you can add any third party package into that file without changes across the app."running server on from port:::::::" + port);

How to handle Undefined Routes

we defined default and three other routes in our service. lets handle undefined routes as well. what if user try to enter wrong one or misspell the route. Make sure you add this route as a last route. if you add this at the beginning all the routes will urls will be redirected to this.

// request to handle undefined or all other routes
app.get("*", function(req, res) {"users route");
res.send("App works!!!!!");

How to define Context Path

we don’t have any context path for our project, Let’s define it. Since it is an api, lets define “/api” for all the routes and also define sub contextpath for the user module which is “/user”.

after the below changes to all the files, path changes from http://localhost:3070/users to http://localhost:3070/api/user/users

// changes - create separate folder routes and two files under it
mkdir routes
cd routes
touch routes.js user.js

Linting your project

Let’s add eslint to our project. it’s very important to have linting for your project to maintain same coding standards across your team. run following commands in a sequence

// installs eslint global so that you can use eslint
npm install -g eslint
//installs eslint for the project
npm install eslint -save-dev
//it will create .eslintrc.js, while creating it will create bunch //of questions like which standards you want to use etc..
eslint --init
//add these below to scripts section in package.json
"eslint": "eslint ./",
"eslint-fix": "eslint ./ --fix",
eslint — lint

when you first run the below command you will have lot of eslint errors you can easily fix all these with the second command

npm run eslint
npm run eslint-fix
eslint errors

with second command you can fix all the errors, if not fix it manually until you fix all the errors. warnings are fine.

errors with eslint

we have added two files for linting and package.json looks like it

Testing your project

coming soon

Production Phase

  • webpack setup
  • environment variables
  • Dockerize the app

Webpack setup

once development is complete, we need to bundle our app and deploy into other environments like stage,uat and prod etc. Let’s add webpack to our project to bundle the entire app files into single file.

install the following to setupp webpack

// install webpack global
npm install -g webpack
//install webpack and webpack-cli in the project
npm install webpack webpack-cli --save-dev
// add below to scripts section in package.json
"build": "webpack"

add the webpack.config.js where you mention starting file and output directory and target is important because our runtime environment is node.

when you run the below command webpack will build the entire project into single bundle file and place that in the target folder mentioned in the webpack.config.js

npm run build
webpack build

after the build complete, lets add the below npm script to the scripts section in the package.json and run the command

"prod": "node dist/api.bundle.js",
npm run prod //run this in the terminal

Environment variables

coming soon

Dockerize the app

Let’s containerize this app. Below is the article about how to build the image and run the app in the container. have a look:)

Thanks for reading.

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