Building a Serverless Next.js App with Vercel and AWS Lambda

Introduction

Serverless architecture has revolutionized modern web development by abstracting infrastructure management and enabling developers to focus on writing code. When combined with Next.js—a powerful React framework—you can build highly scalable, performant, and cost-effective applications.

In this guide, we’ll explore how to deploy a Next.js application on Vercel while leveraging AWS Lambda for serverless backend functionality. This setup allows you to harness the benefits of both platforms: Vercel’s seamless Next.js hosting and AWS Lambda’s scalable compute power.

Why Use Vercel and AWS Lambda Together?

Vercel is the ideal platform for hosting Next.js applications, offering features like automatic deployments, edge caching, and serverless function support. However, for more complex backend logic—such as database operations, third-party API integrations, or heavy computations—AWS Lambda provides a robust, scalable solution.

By combining these tools, you can:

Optimize performance: Serve static and dynamic content via Vercel while offloading compute-heavy tasks to Lambda.
Reduce costs: Pay only for the compute time used in Lambda, avoiding idle server expenses.
Scale effortlessly: Both Vercel and Lambda automatically scale with traffic demands.

Setting Up a Next.js App with Vercel

First, let’s create a Next.js app and deploy it to Vercel.

Initialize a Next.js project:

npx create-next-app@latest my-serverless-app  
cd my-serverless-app

Deploy to Vercel:
- Push your project to a Git repository (GitHub, GitLab, or Bitbucket).
- Sign in to Vercel and import your repository.
- Vercel will automatically detect the Next.js app and configure the deployment.
Verify the deployment:
Once deployed, Vercel provides a live URL for your app.

Integrating AWS Lambda with Next.js

Now, let’s connect AWS Lambda to handle backend logic. We’ll use the AWS SDK to invoke Lambda functions from Next.js API routes.

Step 1: Create an AWS Lambda Function

Log in to the AWS Console and navigate to Lambda.
Create a new function with Node.js runtime.
Write a simple Lambda function, e.g., a greeting service:

exports.handler = async (event) => {  
  const { name } = JSON.parse(event.body);  
  const response = {  
    statusCode: 200,  
    body: JSON.stringify(`Hello, ${name || 'World'}!`),  
  };  
  return response;  
};

Deploy the function and note its ARN (Amazon Resource Name).

Step 2: Configure AWS Credentials

To call Lambda from Next.js, you’ll need AWS credentials. Store these securely using environment variables in Vercel:

Create an IAM user in AWS with lambda:InvokeFunction permissions.
Add the credentials to Vercel:
- In your Vercel project, go to Settings > Environment Variables.
- Add AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.

Step 3: Call Lambda from Next.js API Routes

Create an API route in Next.js (pages/api/greet.js) to invoke the Lambda function:

import { LambdaClient, InvokeCommand } from "@aws-sdk/client-lambda";  

export default async function handler(req, res) {  
  if (req.method !== "POST") {  
    return res.status(405).json({ error: "Method not allowed" });  
  }  

  const client = new LambdaClient({  
    region: "us-east-1", // Update to your region  
  });  

  const params = {  
    FunctionName: "your-lambda-function-arn",  
    Payload: JSON.stringify(req.body),  
  };  

  try {  
    const command = new InvokeCommand(params);  
    const data = await client.send(command);  
    const response = JSON.parse(Buffer.from(data.Payload).toString());  
    res.status(200).json({ message: response });  
  } catch (error) {  
    res.status(500).json({ error: "Failed to invoke Lambda" });  
  }  
}

Step 4: Test the Integration

Deploy the updated Next.js app to Vercel.
Call the API route from your frontend:

const handleGreet = async () => {  
  const response = await fetch("/api/greet", {  
    method: "POST",  
    body: JSON.stringify({ name: "Next.js" }),  
  });  
  const data = await response.json();  
  console.log(data.message); // Output: "Hello, Next.js!"  
};

Optimizing the Serverless Workflow

To enhance your setup, consider the following best practices:

Use Vercel Serverless Functions for Lightweight Tasks:
For simple backend logic (e.g., form submissions), use Vercel’s built-in serverless functions instead of Lambda to reduce latency.
Enable Caching:
Cache Lambda responses where possible to minimize costs and improve performance.
Monitor Performance:
Use AWS CloudWatch and Vercel Analytics to track function invocations, errors, and response times.
Secure Your APIs:
Add authentication (e.g., JWT) to your API routes to prevent unauthorized access.

Conclusion

Combining Next.js, Vercel, and AWS Lambda creates a powerful, scalable, and cost-efficient architecture for modern web applications. Vercel simplifies frontend hosting and deployment, while Lambda handles complex backend operations seamlessly.

By following this guide, you’ve learned how to:

Deploy a Next.js app on Vercel.
Create and invoke AWS Lambda functions from Next.js API routes.
Optimize the integration for performance and security.

This approach empowers developers to build full-stack applications without managing servers, focusing instead on delivering exceptional user experiences. Happy coding!

"Building a Serverless Next.js App with Vercel and AWS Lambda"