This content originally appeared on DEV Community and was authored by Márcio Coelho
AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers. AWS SAM (Serverless Application Model) is an open-source framework that makes building and deploying serverless applications easier. In this guide, we will walk through setting up an AWS Lambda function using Node.js and AWS SAM.
Step 1: Create a New AWS SAM Application
To begin, open a terminal and run:
sam init
Select the following options when prompted:
Template source: AWS Quick Start Templates
Runtime: nodejs22.x (or latest available)
Package type: Zip
Project name: aws-sam-node-lambda
Once completed, navigate to the project directory:
cd aws-sam-node-lambda
Step 2: Understanding the Project Structure
Your SAM project contains several files and folders:
aws-sam-node-lambda/
├── functions
│ ├──hello-world/
│ ├── app.js # Lambda function code
│ ├── package.json # Node.js dependencies
│ ├── tests/ # Unit tests
├── template.yaml # AWS SAM template defining resources
The template.yaml file is crucial as it defines your AWS resources.
Step 3: Writing the Lambda Function
Modify hello-world/app.js to:
exports.lambdaHandler = async (event, context) => {
return {
statusCode: 200,
body: JSON.stringify({
message: "Hello from AWS Lambda with Node.js and SAM!"
})
};
};
Step 4: Build and Test Locally
Before deploying, build the function:
sam build
To invoke it locally:
sam local invoke HelloWorldFunction
Expected output:
{
"statusCode": 200,
"body": "{\"message\":\"Hello from AWS Lambda with Node.js and SAM!\"}"
}
This content originally appeared on DEV Community and was authored by Márcio Coelho
Márcio Coelho | Sciencx (2025-03-31T13:55:14+00:00) Mastering Serverless with AWS SAM. Retrieved from https://www.scien.cx/2025/03/31/mastering-serverless-with-aws-sam/
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