How to Build RESTful APIs with Node.js as an Expert Developer

Tue, 28.02.2023
Mohsinali Chidi
Co-Founder & COO
How to Build RESTful APIs with Node.js as an Expert Developer

I. Introduction

Modern web development must include the RESTful APIs build in Node.js. It allows applications to communicate with one another via the internet without being limited by platform or language. Representational State Transfer, or REST, is a set of architectural guidelines used to develop web services. Application Programming Interfaces, or APIs, are the collection of guidelines or standards used to create software applications. They specify how various software elements ought to communicate with one another.

Node. JS is a well-known and frequently used server-side platform that is based on Chrome’s V8 JavaScript engine. JavaScript helps developers to create scalable and quick online apps. Because of its event-driven, non-blocking I/O style, which enables it to manage a high number of connections without clogging up the server’s resources, Node.js is a strong option for developing RESTful APIs.

In this blog post, I’ll talk about a project I’m working on that involves creating a RESTful API using Node.js. A database’s records may be created, read, updated, and deleted via the API. The project’s objectives are to obtain practical experience in creating scalable and reliable APIs as well as knowledge of how to design and develop a RESTful API using Node.js.

II. Project Setup

Installing Node.js and NPM (Node Package Manager) will allow us to begin constructing the RESTful API on our system. The project’s dependencies and package requirements are managed using NPM.

The steps to install Node.js and NPM are as follows:

  1. Get Node.js from the official website in the most recent version.
  2. Follow the installation wizard’s instructions to install Node.js on your machine.
  3. NPM will be installed automatically when Node.js has been set up.

The npm init command must be used to start a new Node.js project once Node.js and NPM have been installed. This command will generate a package.json file containing the project’s dependencies and information.

The steps to start a new Node.js project are as follows:

  1. Launch a command prompt or terminal.
  2. Locate the directory where the project will be created.
  3. Execute the next command: npm init

You will be prompted by this command to provide information about the project, like its name, version, description, creator, etc. Enter the information or hit Enter to accept the defaults.

Installing the necessary dependencies and development dependencies is necessary once the project has been built. Dev dependencies are the packages needed for development and testing, whereas dependencies are the packages needed for the project to execute. The requirements and development dependencies needed for our project are listed below:

Required dependencies:

  1. Express, a well-liked Node.js web application framework
  2. Body-parser – A middleware for decoding requests’ JSON and URL-encoded data
  3. Mongoose, a library for Object Data Modeling (ODM) in MongoDB
  4. Nodemon – A program that keeps track of source code modifications and restarts the server automatically.

Developer dependencies:

  1. Mocha, a Node.js testing framework
  2. Chai, a Node.js assertion library that supports BDD/TDD.
  3. Supertest – An HTTP request/response testing library.

Run the command below in the terminal to install these dependencies:

npm install express body-parser mongoose nodemon –save
npm install mocha chai supertest –save-dev

III. Creating the API

The next step is to design the REST API by selecting the HTTP methods to use for each endpoint, defining the endpoints and their functionality, and choosing the data format to use for request and response bodies. This is done after you have decided on the fundamental structure and functionality of your REST API.

A. Selecting the appropriate HTTP methods for each endpoint

The action to be taken on a resource is specified via HTTP methods. GET, POST, PUT, DELETE, and PATCH are the most frequently used HTTP methods in REST APIs.

Whereas POST is used to create a new resource, GET is used to get one. Whereas DELETE is used to remove a resource, PUT is used to update an existing resource. PATCH is used to update an existing resource in part.

When selecting the proper HTTP method for each endpoint, you should take the endpoint’s function and the action that needs to be taken on the resource. Use the GET method, for instance, if the endpoint is used to obtain a list of resources. Use the POST method if the endpoint is being used to create a new resource.

B. Outlining the endpoints’ capabilities

Endpoints are URLs that stand in for a single resource or a group of resources. They are used to define both the resource’s location and the action that will be taken on it. For instance, a GET call to the endpoint “/users” may result in the return of a list of users.

The resources that the APIs must expose and the actions that may be taken on those resources should be taken into account while specifying the endpoints and their functionality. Endpoints for creating, obtaining, updating, and removing users, for instance, might be defined if the APIs is used to manage users.

C. Selecting a data format for request and response bodies

Based on the demands of the client application and the APIs, the data format for request and response bodies should be selected. JSON and XML are the most frequently utilised data types in RESTful APIs.

JSON is a lightweight data format that is simple to read and write. Due to the fact that all current browsers support it, it is often used in online applications. Enterprise applications often employ XML, a more verbose data format.

You should take the demands of the client application and the requirements of the APIs into account when choosing the data format to use for request and response bodies. For instance, you should utilise JSON if the client application is a web application that has to consume the APIs data via JavaScript.


Let’s look at an example of a RESTful APIs for managing books. The following endpoints will be defined:

  • GET /books – returns a list of all books
  • GET /books/{id} – returns a single book by ID
  • POST /books – creates a new book
  • PUT /books/{id} – updates an existing book by ID
  • DELETE /books/{id} – deletes a book by ID
  • We will use JSON as the data format for request and response bodies.

Here’s an example of what the response for GET /books might look like:

  "books": [
      "id": 1,
      "title": "The Great Gatsby",
      "author": "F. Scott Fitzgerald",

IV. Implementing the API

Implementing the API comes next after designing it. This entails setting up a server, putting API endpoints into place, and providing middleware to handle things like authentication and error handling.

A. Configuring a server using the built-in http module of Node.js or a more sophisticated framework like Express or Koa

You may use Node.js’ built-in http module to create a server or a more complex framework like Express or Koa. A low-level API for managing HTTP requests and answers is the http module. It offers the fundamental features required to build a server, pay attention to incoming requests, and send back replies.

Higher-level frameworks built on top of the http module include Express and Koa. They provide more sophisticated functionality like routing, middleware support, and simpler administration of complex requests and answers. Express is the more often-used option, although Koa is gaining popularity because of its more contemporary and adaptable style.

Here is an example of how to configure a server using the http module:

const http = require('http');

const server = http.createServer((req, res) => {
  // handle incoming requests

server.listen(3000, () => {
  console.log('Server listening on port 3000');

Here’s an example of how to configure a server using Express:

const express = require('express');

const app = express();

app.listen(3000, () => {
  console.log('Server listening on port 3000');

B. Putting the API endpoints into use using the selected HTTP capability and methods

When the server has been configured, you may begin developing the API endpoints. Each endpoint of the API corresponds to a particular resource or feature. You may include endpoints for publishing and locating posts, following and unfollowing individuals, and like and commenting on posts if you’re developing a social networking application, for instance.

You must choose an HTTP method that matches the endpoint’s capabilities in order to implement it. For instance, you might use the HTTP POST technique to add a new post while using the HTTP GET method to get a list of posts.

Here is an example of how to use Express to construct an endpoint for generating a new post:'/posts', (req, res) => {
  const { title, body } = req.body;
  // create a new post with the given title and body
  res.send('Post created successfully');

C. Adding middleware for handling authentication, error handling, and other features

Middleware is a function that sits between the server and the endpoints, allowing you to add functionality such as authentication, error handling, and logging to your API. Express and other frameworks provide a way to easily add middleware to your API.

Here’s an example of adding middleware for error handling using Express:


app.use((req, res, next) => {
  console.log(`${req.method} ${req.url}`);

app.use((err, req, res, next) => {
  res.status(500).send('Something went wrong!');

V. Testing the API

It is essential to properly test the RESTful APIs after putting it into use using Node.js to make sure it works as expected. The many testing approaches that may be used to test the RESTful APIs will be covered in this section.

A. Unit testing the API endpoints

Little pieces of code, such as functions or methods, are tested individually in unit testing, a sort of testing. The separate pieces of code in RESTful APIs are called API endpoints. Using a testing framework like Jest or Mocha, we can create unit tests for the APIs endpoints.

An example of a Jest test case for a GET request to fetch a user list is shown below:

test('GET /users returns a list of users', async () => {
  const response = await request(app).get('/users');

In this example, we are using the ‘request’ library to send a GET request to the ‘/users’ endpoint of our API. We then expect the response status to be 200 and the response body to contain at least one user.

B. Using tools such as Postman or curl to manually test the endpoints

In addition to unit testing, we can also manually test the API endpoints using tools such as Postman or curl. These tools allow us to send requests to our API and inspect the responses.

Here is an example of using curl to send a GET request to retrieve a list of users:

curl http://localhost:3000/users

In this example, we are using the ‘curl’ command to send a GET request to the ‘/users’ endpoint of our API running on ‘localhost:3000’.

C. Automating tests using a testing framework such as Jest or Mocha

In addition to manual testing and unit testing, we can also automate tests using a testing framework such as Jest or Mocha. Automated tests can be run continuously as part of a CI/CD pipeline to ensure that changes to the codebase do not introduce bugs or regressions.

Here is an example of a Jest test suite that tests all the API endpoints:

describe('API endpoints', () => {
  test('GET /users returns a list of users', async () => {
    // Test code

  test('POST /users creates a new user', async () => {
    // Test code

  test('PUT /users/:id updates an existing user', async () => {
    // Test code

  test('DELETE /users/:id deletes an existing user', async () => {
    // Test code

In this example, we are using Jest to define a test suite for the API endpoints. Each test case tests a different endpoint and its functionality.

VI. Continuous Integration/Continuous Deployment (CI/CD) and Deployment

It’s time to deploy the RESTful API to a production environment once it has through testing. We will go through the process of building up a CI/CD pipeline, configuring the production environment, and deploying the API to a hosting company in this part.

A. Setting up the API’s production environment

The next step is to setup the production environment after the API is prepared for deployment. Given that end users will utilize it, the production environment should be set up differently from the development environment. The production environment may be configured using the following steps:

  1. Configure environment variables: Sensitive data, such as API keys and database login credentials, should be stored in environment variables. It is advised to utilize environment variables to save such data in the production environment.
  2. Install dependencies: Prior to deploying the API, the production server should have all of the requirements installed.
  3. Setup the server: The web server, database server, and any other server components necessary for the successful operation of the API should all be properly setup on the production server.

B. Building up a CI/CD pipeline with technologies like CircleCI or Jenkins

The procedure for developing, testing, and delivering the code is automated via a CI/CD pipeline. The pipeline is made up of numerous steps, including developing the code, running tests, delivering it to a staging environment, and then deploying it to a live environment. Here are some procedures for setting up a CI/CD pipeline using applications like CircleCI or Jenkins:

  1. Set up the pipeline: The pipeline has to be set up in accordance with the project’s specifications. This includes setting up the deployment environment, providing the build and test instructions, and configuring the pipeline phases.
  2. Prepare the deployment environment: The pipeline’s deployment environment should be prepared, which involves setting up the server to accept the code and the production environment.
  3. Set up the deployment process: After the deployment process is set up, it is necessary to describe the deployment strategy, such as whether to transfer the code to the server manually or make use of a deployment tool.

C. Uploading the API to a web server like Heroku or Amazon

The moment has come to deploy the API to a hosting company like Heroku or Amazon once the CI/CD pipeline has been set up. To deploy the API, follow these steps:

  1. Open an account: To begin, open an account on the website of the hosting company.
  2. Make a new app: After making an account, go to the website of the hosting company and create a new app. Depending on the hosting company, there are different procedures for developing new apps.
  3. Release the code: Use the deployment strategy indicated in the CI/CD pipeline to release the code to the hosting provider.

A Node.js app deployment code sample for Heroku:

1. Installing the Heroku CLI first

npm install -g heroku

2. Make a new Heroku application:

heroku create <app-name>

3. Add a Procfile, then:

web: node index.js

4. Push the changes to Heroku and commit them:

git add .
git commit -m "Deploy to Heroku"
git push heroku master

VII. Summary

In conclusion, using Node.js to create RESTful APIs provides a strong and adaptable technique to create online apps. It is feasible to create APIs that are both simple to use and robust enough to handle sophisticated applications with the appropriate tools and methodologies. We hope that this blog article has provided you with a solid foundation for creating your own APIs and that you will continue to explore and learn about this innovative technology.

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Frequently asked questions

chevron down How do I implement the API endpoints using the chosen HTTP methods and functionality in my Node.js REST API?

You can implement the API endpoints using the Express.js framework and the corresponding HTTP methods and functionality in your Node.js REST API.

chevron down What are dependencies and dev dependencies, and how do they differ?

Dependencies are modules that are required for your application to run, while dev dependencies are modules that are only required during development or testing.

chevron down How do I create a new Node.js project using npm init?

You can create a new Node.js project using npm init by running the command "npm init" in your terminal and following the prompts.

chevron down How do I configure the production environment for my Node.js REST API?

You can configure the production environment for your Node.js REST API by setting environment variables, optimizing your code for performance, and using a process manager like PM2 to keep your application running continuously.