AWS Builder Center

Builder Center

Build Your First Serverless API with AWS Lambda and API Gateway 🚀

Build Your First Serverless API with AWS Lambda and API Gateway 🚀

Learn how to build and deploy a simple serverless REST API using AWS Lambda and Amazon API Gateway, without managing traditional servers.

Sanskar

Introduction

Serverless computing is a great way to start learning cloud development because you can focus on writing application logic instead of managing servers.
In this tutorial, we'll build a simple Hello World REST API using AWS Lambda and Amazon API Gateway.

Architecture

1
2
3
4
5
6
7
8
9
10
Client
│
â–¼
API Gateway
│
â–¼
AWS Lambda
│
â–¼
JSON Response

Step 1: Create an AWS Lambda Function

Create a new Lambda function using the Python runtime.
Use the following code:
1
2
3
4
5
6
7
8
9
10
11
12
13
import json

def lambda_handler(event, context):
return {
"statusCode": 200,
"headers": {
"Content-Type": "application/json"
},
"body": json.dumps({
"message": "Hello from AWS!",
"status": "success"
})
}
Deploy the function and test it using the Lambda console.

Step 2: Create an API Gateway

Create an HTTP API in Amazon API Gateway and connect it to your Lambda function.
Create a route such as:
1
GET /hello
API Gateway will provide an HTTP endpoint that can be used to invoke the Lambda function.

Step 3: Test the API

You can test the endpoint using a browser, Postman, or curl.
1
curl https://your-api-url/hello
The API should return:
1
2
3
4
{
"message": "Hello from AWS!",
"status": "success"
}

How It Works

When a client sends a request, API Gateway receives it and invokes the Lambda function.
Lambda executes the Python code and generates a JSON response, which API Gateway sends back to the client.
This means you can build a functional backend without provisioning or managing a traditional server.

What You Can Build Next

Once the basic API works, you can extend it into a real application by adding:
  • Amazon DynamoDB for data storage
  • Authentication and authorization
  • Multiple API endpoints
  • Input validation
  • CloudWatch monitoring
  • A React or mobile frontend
For example:
1
2
3
4
POST /products
GET /products
GET /products/{id}
DELETE /products/{id}
This basic architecture can become the backend for applications such as a task manager, product catalog, attendance system, or e-commerce application.

Important Note

Serverless does not necessarily mean completely free. Costs depend on usage and the AWS services and resources you create.
When experimenting, monitor your AWS resources and remove anything you no longer need.

Conclusion

AWS Lambda and API Gateway provide a simple way to start building serverless applications on AWS.
Start with a small API, connect it to a database, add authentication, and gradually turn it into a complete cloud application.
Build. Test. Learn. Repeat. 🚀
# aws-lambda# serverless# claude-code
Any opinions in this article are those of the individual author and may not reflect the opinions of AWS.
Enjoyed reading this content? Let the author know!

Your likes, comments, shares, and saves help creators reach more builders.

Loading recommendations

Loading article