Deploy a Express JS app in Lambda AWS

Introduction

Lambda is a AWS service that provides the server-less application that is easy to run application without maintaining server. It is not expensive and always free under 1000 000 requests. There is no need to use any other service in lambda you just can deploy with Function URL. In this demonstration I will provide the exact steps that you need to follow in order to deploy this application.

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Steps 📚

Create a Node JS server

1) Create Directory for application

mkdir lambda-express
cd lambda-express

2) Initialization

npm init

3) Install Express

npm install express

Implementing application

• This is a simple 'Hello World' application here is the code

1) Creating the file

touch index.js

2) Code of the application

const express = require('express')
const serverless = require('serverless-http')
const app = express()
const port = 3003

app.use(express.json());

app.get('/', (req, res) => {
    res.send('Hello World!');
});



if(process.env.ENVIRONMENT === "lambda") {
    module.exports.handler = serverless(app);
} else {
    app.listen(port, () => {
        console.log(`Example app listening on port ${port}`)
    });
}

3) Test it is running on port 3003

node index.js

Deploy on AWS 🚀

1) Create the .zip file

zip -r lambda.zip node_modules index.js package.json

• you can use this command to create the zip file or you can download this file -> lambda.zip

2) Create a Lambda function

3) Set Environment Variable

4) Now your App is ready

• You can click Function URL and check the applications is working

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Considerations ❗❗

• This lambda is open to public by Using Public URL
• It might lead to a DDOS attach by someone else
• If you want you can manage lambda by using AWS API Gateway

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Congratulations 🎉 Just now you deployed your app

click your Function URL and enjoy

happy coding !

Comments

[Pruthuvi de Silva]

Great article, Janith! I really enjoyed how clearly you explained the steps to deploy an Express.js app in AWS Lambda. The way you broke down each step made it super easy to follow, even for someone new to serverless architectures. The tip on optimizing the app's size before deployment was especially helpful. Looking forward to more content like this.