Introduction

In modern cloud development, building scalable applications without managing servers has become a standard approach. This is where serverless computing comes into the picture.

AWS Lambda is one of the most popular serverless services that allows you to run code without provisioning or managing servers. When combined with .NET Core, developers can build powerful, scalable, and cost-effective applications using familiar C# skills.

In this article, we will understand how to use AWS Lambda with .NET Core step by step in simple words, along with practical examples and real-world scenarios.

What is AWS Lambda?

AWS Lambda is a serverless compute service provided by Amazon Web Services.

Simple understanding

Think of AWS Lambda as a function that runs only when needed.

Key features

What is .NET Core in Serverless?

.NET Core (now .NET) allows developers to build cross-platform applications using C#.

When used with AWS Lambda:

Why Use AWS Lambda with .NET Core?

Benefits

Real-world example

Imagine a file upload system:

No server is needed.

Prerequisites

Before starting, make sure you have:

Step 1: Install AWS Lambda Tools for .NET

Install the required tools using CLI:

dotnet tool install -g Amazon.Lambda.Tools

This tool helps you create, build, and deploy Lambda functions.

Step 2: Create a New Lambda Project

Run the following command:

dotnet new lambda.EmptyFunction -n MyLambdaApp

This creates a basic AWS Lambda project.

Project structure

Step 3: Write Your Lambda Function

Example:

using System;
using Amazon.Lambda.Core;

[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

public class Function
{
    public string FunctionHandler(string input, ILambdaContext context)
    {
        return $"Hello {input}";
    }
}

What this does

Step 4: Deploy Lambda Function to AWS

Run this command:

dotnet lambda deploy-function MyLambdaApp

What happens here

Step 5: Test the Lambda Function

You can test using AWS Console or CLI.

Example input:

"World"

Output:

"Hello World"

Step 6: Connect Lambda with API Gateway

To expose your Lambda as an API:

Now your function can be accessed via HTTP endpoint.

Example: Simple Web API using Lambda

You can create an API that returns user data.

Step 7: Logging and Monitoring

AWS automatically integrates Lambda with CloudWatch.

What you can track

Why it matters

Helps in debugging and performance tuning.

Step 8: Environment Variables

You can store configuration values in Lambda.

Example:

These can be accessed inside your code.

Step 9: Error Handling

Always handle errors properly.

Example:

try
{
    // logic
}
catch(Exception ex)
{
    context.Logger.LogLine(ex.Message);
    throw;
}

Best Practices

Advantages

Disadvantages

Real-World Use Case

Consider an e-commerce platform:

All without managing servers.

Summary

Using AWS Lambda with .NET Core allows developers to build scalable and efficient serverless applications with minimal infrastructure management. You can write functions in C#, deploy them easily, and integrate with other AWS services like API Gateway and S3. By following best practices and understanding the workflow, you can build production-ready serverless applications that are cost-effective and highly scalable.