Unlocking the Power of Serverless Web Applications: Deploying with AWS Lambda and API Gateway

Serverless web applications are the future. They enable developers to build and deploy scalable applications without worrying about the infrastructure. AWS Lambda and API Gateway are two key AWS services that developers use to create and deploy serverless web applications. In this tutorial, we will guide you through the benefits and how-to steps of creating a serverless architecture for your web apps with AWS Lambda and API Gateway.

What is Serverless Architecture?

Serverless architecture is a cloud computing model where the cloud provider manages the infrastructure and automatically allocates resources as needed. Developers only focus on writing and deploying code. In a serverless architecture, developers don't need to worry about provisioning, scaling, or maintaining servers. They only pay for the resources they use when running an application.

Why Serverless?

Serverless architecture offers significant advantages over traditional server-based architecture:

  • Lower costs: You only pay for the resources you use, reducing costs significantly compared to running and maintaining servers.
  • Greater scalability: Serverless architecture automatically scales according to demand, enabling you to handle unpredictable traffic without provisioning additional resources.
  • Easy deployment: Serverless architecture enables quick and easy deployment of apps without having to worry about the underlying infrastructure.

Getting Started

The first step to building a serverless web application is to create and deploy your Lambda function. Amazon API Gateway provides a mechanism for running a Lambda function in response to a web request. We will use API Gateway to receive incoming web requests and invoke our Lambda function.

Let's launch the AWS Management Console and set up the environment.

1. Create a Lambda Function

The Lambda function is the heart of any serverless architecture. The Lambda function is where all the application logic resides.

Here's how we can create a new Lambda function in the AWS Management Console:

1. Log in to the AWS Management Console. 2. Select the Lambda service. 3. Click on the "Create Function" button. 4. Select the "Author from scratch" option. 5. Give your function a name. 6. Select the runtime environment. 7. Set the handler to the name of your function file and the name of the function to be called within that file. 8. Click the "Create function" button.

Now that we have created a Lambda function, we need to add code to it. You can write the function in any of the supported languages. AWS Lambda supports a wide range of programming languages, including Java, Node.js, and Python. For this tutorial, we will use Node.js.

2. Add Code to the Lambda Function

Once we have created a new function, we can add code to it. The code will be executed by AWS Lambda whenever the function is called. Here is an example code for a simple "Hello World" function:

exports.handler = async (event) => { const response = { statusCode: 200, body: JSON.stringify('Hello World!'), }; return response; };

The function takes a single argument, event, which contains the data that triggered the function. The function returns a JSON object with a status code and a message.

3. Deploy the Function

We now have a functioning Lambda function, but how do we make it accessible from the web?

To make our Lambda function accessible, we need to deploy it. Deployment makes the function available for API Gateway to call and pass to it any relevant event data for processing. Here is how to deploy it:

1. Click on the "Action" button on the AWS Lambda console. 2. Click on "Deploy API." 3. Select an existing deployment stage or create a new one. 4. Click on the "Deploy" button.

Congratulations! You have successfully made your Lambda function accessible from the web.

4. Configure API Gateway

The next step is to configure API Gateway to invoke the Lambda function whenever a web request is received.

Here's how to configure API Gateway:

1. Log in to the AWS Management Console. 2. Go to the Amazon API Gateway Service. 3. Click on "Create API." 4. Select "REST API" as the API type. 5. Select "New API." 6. Give your API a name and description. 7. Click on the "Create API" button. 8. Click on the "Create Resource" button. 9. Give your resource a name and path. 10. Click on the "Create Resource" button. 11. Create a new method by clicking on the dropdown menu of the newly created resource. Select "POST". 12. Select "Lambda Function" as an integration type. 13. Select the Lambda region and corresponding function name. 14. Click on the "Save" button to save the configuration.

API Gateway is now configured with your Lambda function.

5. Test Your Serverless Web Application

Your serverless web application is now ready to be tested. You can test it in several ways:

  • Using the API Gateway Console: You can use the API Gateway console to test your application by selecting the API and clicking on "Test" in the navigation pane.
  • Using a REST Client: You can use a REST client, such as Postman or cURL, to test your application by sending HTTP requests to the API Gateway URL.


Serverless architecture is a significant shift in how applications are architected and deployed. AWS Lambda and API Gateway provide an excellent platform for building and deploying serverless web applications. With serverless architecture, developers can focus on building great applications without worrying about the underlying infrastructure. Follow the instructions above to get started with deploying your first serverless web application on AWS.