What I Learned After Building My First AWS S3 API in .NET (Using Local Stack)

Introduction
When I started learning AWS, I made one mistake that many developers make—I jumped directly into multiple AWS services.
Later I realized the best approach is to master one service at a time.
So I started with Amazon S3, but instead of using a real AWS account, I used Local Stack to simulate AWS services locally.
It turned out to be one of the best decisions for learning.

What I Built
I created a simple ASP.NET Core Web API that can:
Upload files
Download files
Delete files
List files
Everything runs locally using Docker + Local Stack.
No AWS bill.
No IAM configuration.
No internet dependency.

Why Local Stack?
For beginners, Local Stack offers several advantages:
✅ Safe environment to experiment
✅ Fast development cycle
✅ No AWS charges
✅ Works offline
✅ Easy integration with Visual Studio