Master Serverless Architectures: A Beginner's Guide to Building and Deploying Functions with AWS Lambda and Node.js

Are you tired of managing infrastructure for your web applications? Say hello to serverless computing. What is serverless computing? It's a cloud computing model that executes your code in response to events, and you don't have to worry about managing the infrastructure. You only pay for the compute time that you consume, which means you can save a lot of money.

Why Serverless?

The traditional way of building web applications involves managing servers, operating systems, and load balancers, which can be costly and time-consuming. Serverless allows you to focus on writing code that responds to events, without worrying about the infrastructure.

With serverless, you can:

  • Reduce costs: Because you only pay for the compute time that you consume, you can save a lot of money compared to traditional computing models.
  • Scale easily: Serverless computing can handle any amount of traffic, from a few users to millions, without you having to provision any additional infrastructure. Simply write your code, and let the platform handle the rest.
  • Improve time-to-market: With serverless, you can write and deploy code faster, which means you can deliver features to your users more quickly.

AWS Lambda

AWS Lambda is a powerful and widely used serverless computing platform. It lets you run code in response to events, such as a file upload to S3, a new record in DynamoDB, or an HTTP request. You can use AWS Lambda to build highly scalable, cost-effective, and responsive web applications.

AWS Lambda supports several programming languages, including Node.js, Python, Java, and C#. In this tutorial, we'll focus on using Node.js to build our serverless functions.

Setting up your AWS Account

To get started with AWS Lambda, you'll need an AWS account. If you don't already have one, you can sign up for a free account at

Once you have an AWS account, you'll need to create an IAM user with the necessary permissions for working with AWS Lambda. IAM stands for Identity and Access Management, and it's a service that allows you to manage access to AWS services and resources.

Here are the steps to create an IAM user:

  1. Log in to the AWS Management Console.
  2. Click on "Services" in the top menu bar, and select "IAM" from the dropdown list.
  3. In the left-hand navigation panel, select "Users".
  4. Click the "Add user" button.
  5. Enter a name for your user, and select "Programmatic access" as the access type.
  6. Click "Next: Permissions".
  7. Select "Attach existing policies directly".
  8. Find and select the policy called "AWSLambdaFullAccess".
  9. Click "Next: Tags" and "Next: Review".
  10. Review the information, and click "Create user".
  11. Make note of the access key and secret access key provided. You won't be able to see the secret access key again.

Now that you have an IAM user set up, you're ready to create your first function.

Creating Your First Function

To create your first function, you'll need to follow these steps:

  1. Log in to the AWS Management Console.
  2. Click on "Services" in the top menu bar, and select "Lambda" from the dropdown list.
  3. Click the "Create function" button.
  4. Select "Author from scratch", and enter a name for your function.
  5. Choose "Node.js 14.x" as the runtime.
  6. Under "Execution role", select "Use an existing role", and select the role you created earlier.
  7. Click "Create function".

Now that you've created your function, you can start writing code.

Writing Your First Function

Let's write a simple "Hello World" function to get started. Here's the code:

exports.handler = async function(event, context) {
  return {
    statusCode: 200,
    body: "Hello, world!"

This code exports a function called "handler" that takes two parameters: an "event" object and a "context" object. The "event" object contains information about the event that triggered the function, such as an HTTP request. The "context" object provides information about the execution environment, such as the AWS region and the function name.

The function returns a response with a status code of 200 (indicating a successful response) and a body of "Hello, world!".

Let's test our function.

Testing Your Function

To test your function, follow these steps:

  1. Open your function in the AWS Lambda console.
  2. Click the "Test" button.
  3. Create a new test event by clicking "Configure test events".
  4. Enter a name for your test event.
  5. Replace the default event code with this JSON:
  "body": null,
  "resource": "/",
  "path": "/",
  "httpMethod": "GET",
  "isBase64Encoded": false,
  "queryStringParameters": null,
  "multiValueQueryStringParameters": null,
  "pathParameters": null,
  "stageVariables": null,
  "headers": null,
  "multiValueHeaders": null,
  "requestContext": {
    "accountId": "",
    "resourceId": "",
    "stage": "",
    "requestId": "",
    "identity": {
      "cognitoIdentityPoolId": null,
      "accountId": null,
      "cognitoIdentityId": null,
      "caller": null,
      "sourceIp": "",
      "accessKey": null,
      "cognitoAuthenticationType": null,
      "cognitoAuthenticationProvider": null,
      "userArn": null,
      "userAgent": "",
      "user": null
    "resourcePath": "/",
    "httpMethod": "GET",
    "extendedRequestId": "",
    "requestTime": "",
    "path": "/",
    "protocol": "",
    "stageVariables": null,
    "domainPrefix": "",
    "requestTimeEpoch": 0,
    "requestId": "",
    "apiId": ""

This event simulates an HTTP GET request to your function.

Click "Create".

Finally, click "Test" to run your function.

Your function should return a response with a status code of 200 and a body of "Hello, world!". Congratulations, you've just created and tested your first serverless function!

Deploying Your Function

Now that you've tested your function, you're ready to deploy it. Follow these steps to deploy your function:

  1. Click the "Deploy" button in the AWS Lambda console.
  2. Choose a deployment package type. For Node.js, you can choose either a .ZIP file or a .tar.gz file.
  3. Upload your deployment package.
  4. Click "Deploy".

That's it! Your function is now live and ready to handle events. You can test it by sending events to it, such as an HTTP request, a file upload, or a message from an AWS service like SNS or SQS.


In this article, we've learned the basics of serverless computing, and how to build a serverless function using AWS Lambda and Node.js. We've seen how serverless can help reduce costs, improve scalability, and speed up the time-to-market for your web applications. We've also seen how easy it is to set up and deploy a serverless function using AWS Lambda.

If you're interested in learning more about serverless computing, keep exploring the AWS ecosystem, and try building more complex functions that respond to events from multiple services. With serverless, the sky's the limit!