NestJS Serverless

NestJS is a powerful Node.js framework built with TypeScript, ideal for building scalable server-side applications. But did you know you can deploy NestJS in a serverless architecture?

In this guide, we'll explore how to deploy a NestJS app to AWS Lambda using the Serverless Framework.

Why Serverless?

Serverless architecture offers benefits like:

• Cost efficiency (pay-per-use)
• Auto-scaling
• No server management
• Ideal for event-driven applications

Setting Up Your NestJS App

Install dependencies needed for serverless:

npm install --save aws-lambda @codegenie/serverless-express
npm install --save-dev serverless serverless-offline

Configuring Serverless

Create a serverless.yml file at the root of your project:

service: nestjs-serverless

provider:
  name: aws
  runtime: nodejs18.x
  region: ap-southeast-1

plugins:
  - serverless-offline

functions:
  main:
    handler: dist/lambda.handler
    events:
      - http:
          method: ANY
          path: /
      - http:
          method: ANY
          path: "{proxy+}"

Create a Lambda Handler

Create a file lambda.ts in the root:

// lambda.ts
import { NestFactory } from "@nestjs/core";
import serverlessExpress from "@codegenie/serverless-express";
import { Callback, Context, Handler } from "aws-lambda";
import { AppModule } from "./app.module";

let server: Handler;

async function bootstrap(): Promise<Handler> {
  const app = await NestFactory.create(AppModule);
  await app.init();

  const expressApp = app.getHttpAdapter().getInstance();
  return serverlessExpress({ app: expressApp });
}

export const handler: Handler = async (
  event: any,
  context: Context,
  callback: Callback
) => {
  server = server ?? (await bootstrap());
  return server(event, context, callback);
};

Next, open up the tsconfig.json file and make sure to enable the esModuleInterop option to make the @codegenie/serverless-express package load properly.

{
  "compilerOptions": {
    ...
    "esModuleInterop": true
  }
}

Build the NestJS App

Before deploying, build your NestJS project so the compiled files are available in the dist directory:

npm run build

Local Development

Use serverless-offline to run locally:

npx serverless offline

Deploy to AWS

Deploy your application with:

npx serverless deploy

After deployment, you'll get a public URL for your API Gateway endpoint.

Conclusion

Deploying a NestJS app with Serverless on AWS Lambda allows you to build scalable, cost-effective backends. With minimal configuration, you can go from development to production in minutes.