Building a Serverless Application with Node.js and AWS Lambda
Tags: serverless, node, aws, lambda
Published: 2023-06-01 13:32:51


# Building a Serverless Application with Node.js and AWS Lambda

Are you looking for a quick and easy way to create and deploy a serverless Node.js application? Look no further! Serverless applications are becoming more and more popular due to their scalability, ability to handle large workloads quickly, and cost savings. With a serverless application, you can focus on writing code and deploying applications instead of managing and configuring servers. In this article, we’ll walk through how to build a serverless application with Node.js and AWS Lambda. 

To get the most of this tutorial, you should have prior experience working with JavaScript, Node.js, and Amazon Web Services (AWS). We'll be covering the following topics in detail:

- Overview of the Serverless Architecture
- Setting up an AWS Account 
- Creating an AWS Lambda Function 
- Writing an Express Server with Node.js 
- Deploying the Application 

## Overview of Serverless Architecture 

The term “serverless architecture” is misleading because, as a developer, you’ll still be working with servers. The key here is that you don’t need to be the one responsible for managing the servers. Serverless platforms like AWS Lambda take care of the server provisioning and scaling for you. 

The serverless architecture is composed of three main components: 

- **An AWS Lambda Function:** The Lambda function is a piece of code written in a supported language (Node.js, Java, Python, etc.) that is “triggered” or executed when an event occurs. 

- **An Event:** An event is something that triggers the Lambda function, such as a user request to access a web page or data being added to a database. 

- **The Cloud Infrastructure:** The cloud infrastructure is the core of the serverless architecture. This component can be any cloud service provider, such as AWS, Microsoft Azure, or Google Cloud.

## Setting Up an AWS Account 

Before you can create and deploy a Lambda function, you’ll need to create an AWS account. To do this, head over to the [AWS website](https://aws.amazon.com/ "AWS Website") and sign up for an account. After completing the sign-up process, you’ll be asked to configure your account. You can leave all the default settings as-is and click “Continue.” 

Once you’ve set up your account, you’ll be asked to enter your credit card information. Don’t worry — AWS Lambda is free for up to 1 million requests per month. You won’t incur any charges if you stay within the free tier limits. 

Once you’ve entered your credit card information, you’ll be ready to start using the AWS platform. 

## Creating an AWS Lambda Function 

Now that you’ve created your AWS account, you’re ready to create a Lambda function! To do this, navigate to the AWS Management Console. On the left-hand side, you should see various services listed. Select “Lambda” and then click “Create Function.” 

On the next page, you’ll be asked to select a blueprint. A blueprint is essentially a template for a basic Lambda function written in a specific language. For this tutorial, we’ll select the “Hello World” blueprint written in Node.js. Give your function a name (we’ll call it “serverless-app”) and then click “Create Function.” 

You should now be able to see the code for your newly created Lambda function. This code simply prints “Hello World” to the console. Feel free to explore the code and get a better understanding of how Lambda functions work. 

## Writing an Express Server with Node.js 

Now that we’ve created our Lambda function, we can start writing the code for our serverless application. For this application, we’ll be using the popular [Express web framework](https://expressjs.com/ "Express") for Node.js. 

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for developing web and mobile applications. It has a simple API, designed for ease of use, and is the most popular Node.js web framework. 

Let’s start by creating an Express server. Create a new file called `server.js` and add the following code: 

```
const express = require('express');
const app = express();

app.get('/', (req, res) => {
  // Send a response here
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});
```

The code above creates an instance of an Express server and sets up a route for the `/` path. When a request is made to the `/` path, the `GET` handler function will be called. 

## Deploying the Application 

Now that we’ve created the code for our serverless application, we can deploy it to the cloud. To do this, we need to upload our code to AWS Lambda. In the AWS Management Console, select the “serverless-app” function and click the “Upload” button. On the next page, you should see an option to upload a .zip file. Upload your `server.js` file into this field and click the “Upload” button. 

Once the file has been uploaded, you can select the “Test” option in the console. This will trigger the Lambda function and call the `GET` handler function that we wrote. You should see a successful response in the console. 

And that’s it! You now have a fully functioning serverless application running on AWS Lambda. 

## Conclusion 

In this tutorial, we walked through the process of creating a serverless application with Node.js and AWS Lambda. We used the Express web framework to create a simple endpoint that was deployed to the cloud using Lambda. 

We only scratched the surface of what’s possible with serverless applications. If you’d like to learn more about serverless applications, check out [this blog post](https://dev.to/limaleandro1999/getting-started-with-nestjs-a-nodejs-framework-for-building-scalable-applications-547g "Getting Started with NestJS: A Node.js Framework for Building Scalable Applications") on getting started with NestJS and [this blog post](https://dev.to/limaleandro1999/building-a-restful-api-with-typescript-and-express-3i6a "Building a RESTful API with TypeScript and Express") on building a RESTful API with TypeScript and Express. 

Building serverless applications with Node.js and AWS Lambda is a great way to quickly develop and deploy applications without having to worry about servers. Hopefully, this tutorial was helpful in getting you started with serverless applications. 

Happy coding!