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Firdevs Akbayır
Firdevs Akbayır

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Why Top Engineers Are Moving to Serverless (and How You Can Build One with AWS)

#serverless #aws #apigateway #cloud

A step-by-step walkthrough to build your first production-ready serverless API with AWS Lambda and API Gateway.

Introduction

The rise of serverless computing has redefined the way we think about backend development. Instead of setting up servers, configuring runtimes, and worrying about scaling, developers can now focus entirely on writing the core business logic while the cloud provider handles everything else.

Among all the serverless platforms, AWS Lambda paired with API Gateway stands out as one of the most reliable and widely used solutions. With this combination, you can build APIs that are cost-efficient, production-ready, and capable of scaling automatically without manual intervention.

This series aims to break down the process into clear, actionable steps. In this first part, we will focus on AWS Lambda fundamentals—what it is, why it matters, and how to set up your very first function.

Why Serverless?

Traditional backend development required provisioning and maintaining servers, installing software packages, managing operating system updates, and ensuring high availability. While this approach works, it introduces overhead that slows down development and increases costs.

Serverless abstracts away this complexity. You don’t need to worry about servers, scaling policies, or infrastructure patches. Instead, you upload your code and let AWS take care of the rest. This is especially valuable for:

  • Startups and solo developers launching quickly
  • Applications with unpredictable traffic
  • APIs that don’t need 24/7 dedicated servers

AWS Lambda Fundamentals

AWS Lambda is the compute service that powers the serverless model on AWS. It allows you to:

  • Upload small units of code (functions)
  • Run them only when triggered by an event
  • Scale automatically with demand
  • Pay only for the execution time

Lambda functions are event-driven. They can be triggered by many sources such as:

  • API requests (via API Gateway)
  • File uploads (via S3)
  • Database events (via DynamoDB streams)
  • Scheduled tasks (via CloudWatch)

For our API, the main trigger will be API Gateway, but before we connect the two, let’s start by creating a Lambda function.

Step 1: Creating a Lambda Function

  1. Navigate to the AWS Management Console and open the Lambda service.
  2. Click Create function.
  3. Choose Author from scratch.
    • Give your function a name (e.g., myFirstLambda).
    • Select a runtime (Python or Node.js are commonly used).
    • Leave the default permissions for now.

Once the function is created, AWS will provide you with a built-in code editor. Inside, replace the default handler with something simple, such as:

def lambda_handler(event, context):
    return {
        "statusCode": 200,
        "body": "Hello from Lambda!"
    }
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This code will execute whenever your Lambda function is triggered, returning a basic response.

Step 2: Testing the Function

Before connecting Lambda to an external service, you can test it directly in the AWS Console.

  • Click Test in the Lambda dashboard.
  • Provide a sample event (AWS offers templates you can use).
  • Run the test and verify that you receive a 200 OK response with the message.

At this point, you have successfully deployed and executed a Lambda function. However, it is still running in isolation and not yet exposed to the outside world. To turn it into a public API, we need to integrate it with API Gateway.

And this is where the real journey begins. In the next step, we will configure API Gateway, create routes, and connect them to Lambda—so that anyone can access your function through a REST endpoint.

To continue reading and follow the step-by-step deployment, check out the full article on Medium:

At this point, you have successfully deployed and executed a Lambda function. However, it is still running in isolation and not yet exposed to the outside world. To turn it into a public API, we need to integrate it with API Gateway.

And this is where the real journey begins. The next step involves configuring API Gateway, creating routes, and connecting them to Lambda—so that anyone can access your function through a REST endpoint.

You can continue with the full step-by-step deployment in the complete article here:

Building a Serverless API with AWS Lambda & API Gateway (Part 1)

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